Methods, systems and apparatus for defining and using phich resources for carrier aggregation

ABSTRACT

Systems, methods, and instrumentalities are disclosed to provide feedback to a user equipment (UE). A UE may transmit uplink data via a supplementary cell. A network device, such as a HeNB, eNB, etc., may receive the uplink data from the UE via the supplementary cell. The network device may send feedback associated with the uplink data to the UE via a physical downlink shared channel (PDSCH) when downlink data is available for transmission to the UE. The feedback may be physical hybrid ARQ indicator channel (PHICH) ACK/NACK information. The feedback sent via the PDSCH may be multiplexed with the downlink data. The network device may send the feedback associated with the uplink data to the UE via a physical downlink control channel (PDCCH) when downlink data is not available for transmission to the UE.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/496,911, filed on Jun. 14, 2011, the contents ofwhich are hereby incorporated by reference herein.

BACKGROUND

The analog TV bands included the Very High Frequency (VHF) band and theUltra High Frequency (UHF) band. VHF is composed of the low VHF bandoperating from 54 MHz to 88 MHz (excluding 72 MHz to 76 MHz), and thehigh VHF band operating from 174 MHz to 216 MHz. The UHF band iscomposed of the low UHF band operating from 470 MHz to 698 MHz, and thehigh UHF band operating from 698 MHz to 806 MHz

In the United States, the Federal Communications Commission (FCC) setJun. 12, 2009 as the deadline for replacing analog TV broadcasting bydigital TV broadcasting. The digital TV channel definitions may be thesame as the analog TV channel. The digital TV bands may use analog TVchannels 2 to 51 and may not use 37, while the analog TV channels 52 to69 may be used for new non-broadcast users. The frequency allocated to abroadcasting service but not used locally may be referred to as WhiteSpace (WS). TV White Space (TVWS) may refer to the TV channels 2 to 51,which may not include except 37.

Besides TV signals, there are other licensed signals that may betransmitted on the TV bands. Channel 37 may be reserved for radioastronomy and Wireless Medical Telemetry Service (WMTS), where thelatter may operate on any vacant TV channels 7 to 46. The Private LandMobile Radio System (PLMRS) may use channels 14 to 20 in certainmetropolitan areas. Remote control devices may use channels abovechannel 4, except channel 37. The starting frequency of FM channel 200is 87.9 MHz, with partial overlapping on TV channel 6. The wirelessmicrophone may use channels 2 to 51 with a bandwidth of 200 kHz.

As a result of the transition from analog to digital TV transmissions,certain portions of the spectrum may no longer be used for TVtransmissions, though the amount and exact frequency of unused spectrummay vary from location to location. The FCC has opened up these TVWSfrequencies for a variety of unlicensed uses.

The opportunistic use of unlicensed bands, such as TVWS bands, may beexploited by secondary users for any radio communication given that theuse does not interfere with other incumbent and/or primary users. Thereare many problems associated with LTE, and other cellular technologies,use of unlicensed spectrum such as TVWS.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Systems, methods, and instrumentalities are disclosed to providefeedback to a user equipment (UE). A UE may transmit uplink data via asupplementary cell. A network device, such as a HeNB, eNB, etc., mayreceive the uplink data from the UE via the supplementary cell. Thenetwork device may send feedback associated with the uplink data to theUE via a physical downlink shared channel (PDSCH) when downlink data isavailable for transmission to the UE. The feedback may be physicalhybrid ARQ indicator channel (PHICH) ACK/NACK information. The feedbacksent via the PDSCH may be multiplexed with the downlink data. Thenetwork device may send the feedback associated with the uplink data tothe UE via a physical downlink control channel (PDCCH) when downlinkdata is not available for transmission to the UE. The feedback may besent on one or more of a primary component carrier and a secondarycomponent carrier. The feedback may be sent on a best available licensedcell. The feedback may be sent on a supplementary cell.

The feedback sent via the PDCCH may be sent via a downlink controlinformation (DCI) format on the PDCCH. The DCI format may be format 1Cassociated with the PDCCH. A modulation and encoding value associatedwith the DCI format may be used to indicate that the DCI formatcomprises ACK/NACK information. ACK/NACK information associated with thefeedback may be sent in a resource block assignment. The resource blockassignment may be a single resource block using a type 2 allocation.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A illustrates exemplary TV band spectrum usage in the UnitedStates;

FIG. 1B illustrates an exemplary communication system in which one ormore disclosed embodiments may be implemented;

FIG. 1C illustrates an exemplary wireless transmit/receive unit (WTRU)that may be used within the communication system illustrated in FIG. 1B;

FIG. 1D illustrates an exemplary radio access network (RAN) and anexemplary core network (CN) that may be used within the communicationsystem illustrated in FIG. 1B;

FIG. 2 illustrates an exemplary system deploying supplementary carriersto use Dynamic Spectrum Sharing (DSS) bands;

FIG. 3 illustrates an exemplary spectrum allocation in which the FDDlicensed spectrum may be the primary carrier;

FIG. 4 illustrates an exemplary spectrum assignment for a RRC triggeredscenario;

FIG. 5 illustrates an exemplary spectrum allocation in a MAC CEtriggered scenario;

FIG. 6 illustrates an exemplary spectrum allocation in which a FDDprimary cell aggregates with a Time Division Duplexing (TDD)supplementary carrier;

FIG. 7 illustrates exemplary inter-band and inter-band carrieraggregation (CA);

FIG. 8 illustrates an exemplary Physical Hybrid ARQ Indicator Channel(PHICH) group modulation;

FIG. 9 illustrates an exemplary PHICH resource allocation associatedwith a supplementary carrier adjustment;

FIG. 10 illustrates another exemplary PHICH resource allocation usinglinked reserved control channel elements (CCEs);

FIG. 11 illustrates a further exemplary PHICH resource allocation usingreserved CCEs;

FIG. 12 illustrates an exemplary dynamic allocation of PHICH resources;

FIGS. 13, 14 and 15 illustrate exemplary allocation of PHICH resourcesof one of the component carriers;

FIG. 16 illustrates an exemplary mapping of PHICH to reserved resourceblocks of a cell;

FIG. 17 illustrates an exemplary allocation based PHICH resourcedefinition;

FIG. 18 illustrates an exemplary ACK/NACK multiplexing operation;

FIG. 19 illustrates an exemplary supplementary cell uplink (UL) grantoperation;

FIG. 20 illustrates an exemplary supplementary ACK/NACK UL transmission;

FIG. 21 illustrates exemplary allocation of messaging resources; and

FIG. 22 illustrates exemplary allocation of messaging resources.

DETAILED DESCRIPTION

A detailed description of illustrative embodiments may now be describedwith reference to the figures. However, while the present invention maybe described in connection with exemplary embodiments, it is not limitedthereto and it is to be understood that other embodiments may be used ormodifications and additions may be made to the described embodiments forperforming the same function of the present invention without deviatingtherefrom.

The FCC may allow unlicensed radio transmitters to operate in the TVWS,which may not include channels 3, 4 and 37, e.g., as long as minimuminterference is caused to the licensed radio transmissions. UnlicensedTV Band Devices (TVBDs) may be referred to as: (1) a fixed TVBD; (2) amode I portable (e.g., personal) TVBD; and (3) a mode II portable (e.g.,personal) TVBD. Fixed TVBDs and mode II portable TVBDs may havegeo-location database access capability and may register to the TV banddatabase. Access to the TV band database may query the allowed TVchannels to avoid interference with digital TV signals and licensedsignals transmitted on the TV bands. Spectrum sensing may be an add-onfeature for TVBDs, e.g., to enable low interference to be caused todigital TV signals and licensed signals.

FIG. 1A shows exemplary TV band spectrum usage. Fixed TVBDs may operateon channels 2 to 51, which may not include channels 3, 4, 37. TVBDs maynot operate on the same or the first adjacent channel to a channel usedby TV services.

FIG. 1B is a diagram of an exemplary communication system 100 in whichone or more disclosed embodiments may be implemented. The communicationsystem 100 may be a multiple access system that may provide content,such as voice, data, video, messaging, and/or broadcast, among others,to multiple wireless users. The communication system 100 may enablemultiple wireless users to access such content through the sharing ofsystem resources, including wireless bandwidth. For example, thecommunication systems 100 may use one or more channel access methods,such as code division multiple access (CDMA), time division multipleaccess (TDMA), frequency division multiple access (FDMA), orthogonalFDMA (OFDMA), and/or single-carrier FDMA (SCFDMA), among others.

As shown in FIG. 1B, the communication system 100 may include: (1) WTRUs102 a, 102 b, 102 c and/or 102 d; (2) a RAN 104; a CN 106; a publicswitched telephone network (PSTN) 108; the Internet 110; and/or othernetworks 112. It is contemplated that the disclosed embodiments mayinclude any number of WTRUs, base stations, networks, and/or networkelements. Each of the WTRU s 102 a, 102 b, 102 c or 102 d may be anytype of device configured to operate and/or communicate in a wirelessenvironment. By way of example, the WTRUs 102 a, 102 b, 102 c or 102 dmay be configured to transmit and/or receive wireless signals and mayinclude user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal digitalassistant (PDA), a smartphone, a laptop, a netbook, a personal computer,a wireless sensor, and/or consumer electronics, among others.

The communication system 100 may also include a base station 114 a and abase station 114 b. Each of the base stations 114 a or 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRU s 102 a, 102 b, 102 c, and/or 102 d to facilitate access to oneor more communication networks, such as the CN 106, the Internet 110,and/or the other networks 112. By way of example, the base stations 114a and 114 b may be a base transceiver station (BTS), a Node-B, an eNodeB, a Home Node B, a Home eNode B, a site controller, an access point(AP), and/or a wireless router, among others. While the base stations114 a, 114 b are each depicted as a single element, it is contemplatedthat the base stations 114 a and 114 b may include any number ofinterconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 104, which may includeother base stations and/or network elements (not shown), such as a basestation controller (BSC), a radio network controller (RNC), and/or relaynodes, among others. The base station 114 a and/or the base station 114b may be configured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree cell sectors. In certain exemplary embodiments, the base station114 a may include three transceivers, i.e., one for each sector of thecell. In various exemplary embodiments, the base station 114 a mayemploy multiple-input multiple output (MIMO) technology and, may utilizemultiple transceivers for each sector of the cell.

The base stations 114 a and 114 b may communicate with one or more ofthe WTRUs 102 a, 102 b, 102 c and/or 102 d over an air interface 116,which may be any suitable wireless communication link (e.g., radiofrequency (RF), microwave, infrared (IR), ultraviolet (UV) and/orvisible light, among others). The air interface 116 may be establishedusing any suitable radio access technology (RAT).

As noted above, the communication system 100 may be a multiple accesssystem and may employ one or more channel access schemes, such as CDMA,TDMA, FDMA, OFDMA, and/or SC-FDMA, among others. For example, the basestation 114 a in the RAN 104 and the WTRUs 102 a, 102 b and 102 c mayimplement a RAT such as Universal Mobile Telecommunications System(UMTS) Terrestrial Radio Access (UTRA), which may establish the airinterface 116 using wideband CDMA (WCDMA). WCDMA may includecommunication protocols such as High-Speed Packet Access (HSPA) and/orEvolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access(HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In certain exemplary embodiments, the base station 114 a and the WTRUs102 a, 102 b and 102 c may implement a RAT such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In certain exemplary embodiments, the base station 114 a and the WTRUs102 a, 102 b and 102 c may implement RAT such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), and/or GSM EDGE (GERAN), among others.

The base station 114 b in FIG. 1B may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, and/or a campus, among others.In certain exemplary embodiments, the base station 114 b and the WTRUs102 c and 102 d may implement a RAT such as IEEE 802.11 to establish awireless local area network (WLAN). In certain exemplary embodiments,the base station 114 b and the WTRUs 102 c and 102 d may implement a RATsuch as IEEE 802.15 to establish a wireless personal area network(WPAN). In certain exemplary embodiments, the base station 114 b and theWTRUs 102 c and 102 d may utilize a cellular based RAT (e.g., WCDMA,CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell.As shown in FIG. 1B, the base station 114 b may have a direct connectionto the Internet 110. The base station 114 b may access the Internet 110via the CN 106 or may access the Internet directly or through adifferent access network.

The RAN 104 may be in communication with the CN 106, which may be anytype of network configured to provide voice, data, applications, and/orvoice over internet protocol (VoIP) services to one or more of the WTRUs102 a, 102 b, 102 c and/or 102 d. For example, the CN 106 may providecall control, billing services, mobile location-based services, pre-paidcalling, Internet connectivity, video distribution, and/or performhigh-level security functions, such as user authentication, amongothers. Although not shown in FIG. 1B, it is contemplated that the RAN104 and/or the CN 106 may be in direct or indirect communication withother RANs that employ the same RAT as the RAN 104 or a different RAT.For example, in addition to being connected to the RAN 104, which may beutilizing an E-UTRA radio technology, the CN 106 may also be incommunication with another RAN employing a GSM radio technology.

The CN 106 may also serve as a gateway for the WTRUs 102 a, 102 b, 102 cand 102 d to access the PSTN 108, the Internet 110, and/or othernetworks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Theother networks 112 may include wired or wireless communication networksowned and/or operated by other service providers. For example, the othernetworks 112 may include another CN connected to one or more RANs, whichmay employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c and 102 d in thecommunication system 100 may include multi-mode capabilities, (e.g., theWTRUs 102 a, 102 b, 102 c and/or 102 d may include multiple transceiversfor communicating with different wireless networks over differentwireless links). For example, the WTRU 102 c may be configured tocommunicate with the base station 114 a, which may employ acellular-based RAT, and with the base station 114 b, which may employ anIEEE 802 RAT.

FIG. 1C is a system diagram of an exemplary WTRU 102. As shown in FIG.1C, the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 106, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, and/orother peripherals 138, among others. It is contemplated that the WTRU102 may include any sub-combination of the foregoing elements whileremaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), and/or a statemachine, among others. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. Although FIG.1C depicts the processor 118 and the transceiver 120 as separatecomponents, it is contemplated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip. The transmit/receive element 122 may be configured to transmitsignals to, or receive signals from, a base station (e.g., the basestation 114 a) over the air interface 116. For example, in certainexemplary embodiments, the transmit/receive element 122 may be anantenna configured to transmit and/or receive radio frequency (RF)signals. In various exemplary embodiments, the transmit/receive element122 may be an emitter/detector configured to transmit and/or receiveinfrared (IR), ultraviolet (UV), and/or visible light signals, forexample. In some exemplary embodiments, the transmit/receive element 122may be configured to transmit and receive both RF and light signals. Itis contemplated that the transmit/receive element 122 may be configuredto transmit and/or receive any combination of wireless signals.

Although the transmit/receive element 122 is depicted in FIG. 1C, as asingle element, the WTRU 102 may include any number of transmit/receiveelements 122 and/or may employ MIMO technology. In certain exemplaryembodiments, the WTRU 102 may include two or more transmit/receiveelements 122 (e.g., multiple antennas) for transmitting and receivingwireless signals over the air interface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) unit ororganic light emitting diode (OLED) display unit). The processor 118 mayoutput user data to the speaker/microphone 124, the keypad 126, and/orthe display/touch pad 128. The processor 118 may access informationfrom, and store data in, any type of suitable memory, such as thenon-removable memory 106 and/or the removable memory 132. Thenon-removable memory 106 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of fixed memorystorage device. The removable memory 132 may include a subscriberidentity module (SIM) card, a memory stick, and/or a secure digital (SD)memory card, among others. In certain exemplary embodiments, theprocessor 118 may access information from, and store data in, memorythat is not physically located at and/or on the WTRU 102, such as on aserver or a home computer (not shown).

The processor 118 may be configured to receive power from the powersource 134, and may be configured to distribute and/or control the powerto the other components in the WTRU 102. The power source 134 may be anysuitable device for powering the WTRU 102. For example, the power source134 may include one or more dry cell batteries (e.g., nickel-cadmium(NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), and/or lithiumion (Li-ion), among others), solar cells, and/or fuel cells, amongothers.

The processor 118 may be coupled to the GPS chipset 136, which may beconfigured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a and/or 114 b) and/or maydetermine its location based on the timing of the signals being receivedfrom two or more nearby base stations. It is contemplated that the WTRU102 may acquire location information by way of any suitablelocation-determination method.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, and/or anInternet browser, among others.

FIG. 1D is a system diagram of the RAN 104 and the CN 106 according tocertain exemplary embodiments. The RAN 104 may employ the E-UTRA radiotechnology to communicate with the WTRU s 102 a, 102 b and 102 c overthe air interface 116. The RAN 104 may be in communication with the CN106.

Although the RAN 104 is shown to include eNode-Bs 140 a, 140 b and 140c, it is contemplated that the RAN 104 may include any number ofeNode-Bs. The eNode-Bs 140 a, 140 b and 140 c may each include one ormore transceivers for communicating with the WTRUs 102 a, 102 b and 102c over the air interface 116. The eNode-B 140 a, for example, may useMIMO technology or may use multiple antennas to transmit wirelesssignals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 140 a, 140 b and/or 140 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, and/or scheduling ofusers in the UL and/or downlink (DL), among others. As shown in FIG. 1D,the eNode-Bs 140 a, 140 b and 140 c may communicate with one anotherover an X2 interface.

The CN 106 may include a mobility management gateway (MME) 142, a SeGW144, and a packet data network (PDN) gateway 146. Although each of theforegoing elements is depicted as part of the CN 106, it is contemplatedthat anyone of these elements may be owned and/or operated by an entityother than the CN operator.

The MME 142 may be connected to each of the eNode-Bs 142 a, 142 b and/or142 c in the RAN 104 via an S1 interface and may serve as a controlnode. For example, the MME 142 may be responsible for: (1)authenticating users of the WTRUs 102 a, 102 b and 102 c; (2) beareractivation/deactivation; and/or (3) selecting a particular SeGW duringan initial attach (e.g., attachment procedure) of the WTRUs 102 a, 102 band 102 c, among others. The MME 142 may provide a control planefunction for switching between the RAN 104 and other RANs that employother RAT, such as GSM or WCDMA.

The serving gateway (SeGW) 144 may be connected to each of the eNode Bs140 a, 140 b and 140 c in the RAN 104 via the S1 interface. The SeGW 144may generally route and forward user data packets to/from the WTRUs 102a, 102 b and 102 c. The SeGW 144 may perform other functions, such asanchoring user planes during inter-eNode B handovers, triggering pagingwhen DL data is available for the WTRUs 102 a, 102 b and 102 c, and/ormanaging and storing contexts of the WTRUs 102 a, 102 b and 102 c, amongothers.

The SeGW 144 may be connected to the PDN gateway 146, which may providethe WTRUs 102 a, 102 b and 102 c with access to packet-switchednetworks, such as the Internet 110, to facilitate communications betweenthe WTRUs 102 a, 102 b and 102 c and IP-enabled devices.

The CN 106 may facilitate communications with other networks. Forexample, the CN 106 may provide the WTRUs 102 a, 102 b and 102 c withaccess to circuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b and 102 c and traditionalland-line communication devices. For example, the CN 106 may include, ormay communicate with, an IP gateway (e.g., an IP multimedia subsystem(IMS) server) that may serve as an interface between the CN 106 and thePSTN 108. The CN 106 may provide the WTRUs 102 a, 102 b and 102 c withaccess to the other networks 112, which may include other wired orwireless networks that are owned and/or operated by other serviceproviders.

FIG. 2 shows an exemplary system 200 deploying supplementary carriersthat may use Dynamic Spectrum Sharing (DSS) bands. DSS bands may includelicense-exempt bands (e.g., TVWS and ISM). A supplementary componentcarrier may operate in DSS bands. A supplementary component carrier maybe a secondary component carrier, an extension carrier, or carrier typethat may be created. The system may use heterogeneous networkdeployments that may make use of advanced DSS carrier aggregation, e.g.,to provide hot-spot coverage. The heterogeneous network architecture mayinclude an LTE macro cell 210 and an underlay of pico/femto/RRH cells220-1, 220-2 . . . 220-N that may aggregate licensed and DSS bands. Themacro cells 210 may provide service continuity. The pico/femto cells220-1, 220-2 . . . 220-N may be used to provide hot spot coverage. Acoexistence database 230 and mechanisms to coordinate operation withother secondary networks and/or users operating in DSS bands may beimplemented. A TVWS database 240 may be used to protect incumbent usersoperating in the TVWS band. There may be infrastructure to supportdynamic spectrum trading across both licensed and DSS bands. Theinfrastructure may employ a multi-phased approach targeting HeNB 250 forPhase I and RRH/picocell campus type deployments 260 for Phase II.

FIG. 3 shows an exemplary spectrum allocation in which the FDD licensedspectrum may be the primary carrier. The FDD licensed spectrum may beused as the primary carrier or primary cell and a supplementary DSScarrier may be dynamically aggregated with the primary carrier in the ULand/or DL for a given time interval (e.g., a subframe, a frame, or someother interval, etc.). This may ensure that the UE (e.g., a radio orother device) operating in the DSS spectrum does not transmit andreceive in the DSS band simultaneously.

Certain exemplary embodiments may include an FDD primary cellaggregating a dynamic FDD supplementary carrier in which the Primary FDDcarrier (e.g., licensed carrier) may aggregate with a supplementarycarrier based on the existing FDD frame structure and which maydynamically change the supplementary carrier to aggregate in the DLand/or the UL.

FIG. 4 illustrates an exemplary spectrum assignment for a Radio ResourceControl (RRC) triggered scenario. The direction of the aggregation maybe dynamically changed through an RRC reconfiguration sent over theprimary carrier. As an example, LTE may deliver and process RRC messageswithin 15 ms in connected mode.

FIG. 5 illustrates an exemplary spectrum allocation in a MAC CEtriggered scenario. The direction of the aggregation may be dynamicallychanged through a MAC CE command sent over the primary carrier. RRCreconfiguration messages may be used to pre-configure the UL and/or DLsupplementary carrier in the DSS spectrum. A MAC CE message maysubsequently activate the supplementary carrier in one direction anddeactivate it in the other direction, e.g., as shown in FIG. 5.

An UL and DL frame timing may be implemented. For example, a MACscheduler and buffering scheme may be used to retain temporarilydeactivated UL or downlink Mac Protocol Data Units (MPDUs) whenswitching the supplementary carrier from DL to UL or vice versa. FDDcarriers may make aggregation synchronous and additional memory may notbe used.

A Guard Period (GP) may be added for dynamic FDD prior to a frameboundary when switching the supplementary carrier from DL to UL or viceversa. The added GP may be configured based on the range or size of thecell. It may also be changed and/or reconfigured dynamically, e.g., viaRRC reconfiguration messages.

For carrier aggregation, the Physical Hybrid ARQ Indicator Channel(PHICH) may be transmitted on the DL carrier (e.g., limited to one ormore DL carriers) that may have been used to transmit the UL grant. Thetiming of responses to be expected on the PHICH may differ in FDD andTDD. For FDD, DL ACK/NACK may be sent 4 subframes after the ULtransmission, in TDD this may be variable. The mapping of PHICHresources may differ in FDD and TDD. In FDD, the frames (e.g., eachframe) may have the same number of PHICH resource elements in the firstOFDM symbol. In TDD, the number of PHICH resource elements may depend onthe subframe. In TDD, the size of the PHICH resources may be adjustedbased on the UL/DL configuration (e.g., a UL-heavy configuration mayhave more resource elements allocated to the PHICH). In Rel-10, PHICHcollisions may be limited to consideration in the case of cross-carrierscheduling (e.g., resolved by DMRS cyclic shift mechanism).

If an FDD carrier is used in whitespace (e.g., the TVWS), it may resultin an UL heavy configuration, which may have a potential for PHICHcollisions. Certain exemplary embodiments may define additional PHICHallocations which may be sent using (e.g., over) the RRC reconfigurationmessage to configure the supplementary carrier. The PHICH configurationsmay be changed or adjusted when the supplementary carrier isreconfigured from UL to DL, e.g., in order to adapt to the load (e.g.,UL heavy or DL heavy) of the channel. Allocation and configuration ofthe Physical Downlink Control Channel (PDCCH) in the licensed band maybe modified based on PHICH allocations that may occur in the first OFDMsymbol of each subframe.

When the DSS band carrier is set to DL, the DSS band UL controlinformation like channel quality indicator (CQI)/precoding matrixindicator (PMI)/rank indicator (RI), ACK/NACK/discontinuous transmission(DTX) may be sent over the primary carrier FDD UL. The format of thecontrol information may be updated to include corresponding bit fieldson FDD UL for that purpose.

FIG. 6 shows an exemplary spectrum allocation for an FDD primary cellthat aggregates with a TDD supplementary carrier. Certain exemplaryembodiments may be based on a primary FDD carrier (e.g., licensed)aggregating a supplementary carrier based on an existing LTE-TDD frame.Multiple UL and DL supplementary transmission opportunities may exist ineach frame and may depend on the asymmetry configuration (e.g.,configuration #3 is shown).

TDD operation may provide for the UL and/or DL configuration beingfixed, e.g., for the entire cell, so the PHICH resources allocated forUL/DL may be fixed. A dynamic UL and DL configuration may be implementedto dynamically change the configuration of the UL/DL and the PHICHresources allocated for the UL/DL. For example, in TDD, the active WTRUmay be sent UL/DL reconfigurations, e.g., through RRC reconfigurationmessages. This may allow the UL/DL configuration to be adjusted to thetraffic load over the cell. Idle mode WTRUs may not be impacted by thischange, e.g., as camping on the primary carrier or multiple UL/DLconfigurations may be preconfigured through the RRC message andactivated by the MAC CE message. Since CA may not be used in IDLE mode,the change of the UL/DL configuration on these WTRUs may be transparentuntil they move to RRC CONNECTED, e.g., at which time they may havereceived the current UL/DL configuration to be used.

A guard period (GP) may be desired in the special subframe for the TDDsupplementary carrier. This GP duration may be configurable through RRCreconfiguration. This may allow for the configuration to dynamicallyadjust to the range of the cell and the frequency band of the DSSspectrum being used (e.g., the propagation characteristics of the signalmay change as the frequency is changed). A preconfigured GP value perfrequency band may be used. This preconfigured GP may be based on theexpected cell size and may be modified by the RRC message when thefrequency band of the supplementary carrier is changed.

Periodicity and timing of the Sounding Reference Signal (SRS) may becontrolled by upper layer parameters and may be different between TDDand FDD. The SRS may be transmitted in the UL pilot time slot (UpPTS) inTDD (e.g., UpPTS may be reserved for SRS and Format 4 PRACH). Differentsubframe configurations may be sent for each carrier, for example, whenTDD and FDD are configured (e.g., when a TDD supplementary carrier maybe used). This SRS configuration may be sent over the primary carrier.Fields may be added to the SRS configuration to identify whether theconfiguration corresponds to TDD or FDD.

In TDD special frames may have no Physical UL Control Channel (PUCCH)mapped to them. The PUCCH may be transmitted on (e.g., limited totransmission on) the primary cell in an FDD fashion.

The physical random access channel (PRACH) procedures and structure inTDD may be different than FDD. The PRACH in LTE may include six resourceblocks (RBs) adjacent to the PUCCH in predetermined subframes. For agiven PRACH configuration (e.g., from S1B2) mapping to specificsubframes may be different in TDD and FDD. In FDD, one PRACH resourcemay be available per subframe. In TDD, multiple PRACH resources may bein a given subframe (e.g., to account for fewer UL subframes in aframe). The offset between PRACH resources in a subframe may be given bythe upper layers. Preamble format 4 may be used (e.g., by itself) inTDD, for example, in which a short preamble may be used to fit intoUpPTS of the special subframe.

The PRACH may be performed in the primary cell, which may be FDD. Theconfiguration, timing, and procedure for the PRACH may follow the FDDcase. The network may trigger additional PRACH to be performed on thesupplementary carrier in the event that the timing alignment between theprimary and supplementary carrier may be different, e.g., due to a largefrequency separation. In such a case, the RRC reconfiguration associatedwith adding the supplementary carrier may define the specific RandomAccess Channel (RACH) configuration to be used on the supplementarycarrier, which may include a TDD RACH procedure. The RRC configurationthat may be sent over the FDD carrier may indicate that the RACHconfiguration may be specific to the TDD carrier. This type of RACH maybe triggered when the WTRU has data to send to the eNB or when the eNBhas detected a timing drift between the primary and supplementarycarriers.

When performing PRACH on the secondary carrier (e.g., using TDD),contention resolution may take place on the primary or supplementarycarrier, e.g., in order to provide a larger number of available PRACHresources for the system.

UL power control may be implemented. Timing of UL power control for thePUSCH relative to the transmit power control (TPC) command may bedifferent in TDD and FDD. An entity in the eNB may be implemented thatmay be aware of the timing difference between the power control changeson the TDD and FDD carriers and may apply the appropriate TPC command.If cross carrier scheduling is supported, TPC commands for FDD or TDDmay be differentiated. This may be performed by adding a field to thePDCCH for the TPC command or using carrier specific schedule for theTPC.

In LTE, TDD may support bundling of multiple ACK/NACKs into a singleACK/NACK to be sent in the UL subframe. FDD may not support this mode(e.g., a single ACK may be sent for each received transport block). TheACK/NACK bundling may be controlled by the DL Assignment Index (DAI)sent in DL Control Information (DCI) on the PDCCH (e.g., 2 bits inlength). These two bits may not be present in FDD mode DCI formats. Whenmultiple serving cells are configured, the ACK/NACK bundling may not beperformed; multiplexing may be used. The ACK/NACK repetition (e.g., thatmay be configured by upper layers) in TDD mode may be applied for theACK/NACK bundling and may not be used for the ACK/NACK multiplexing.

The cross-carrier scheduling of DL resources may be allowed on the TDDsupplementary carrier via the FDD carrier. For cross carrier scheduling,the FDD carrier may include the DAI in the DCI format and the additionalmodification in blind decoding of PUCCH may be performed. Because theACK/NACK may be sent on the PUCCH, bundling may be supported on the FDDUL carrier (e.g., the eNB may be able to decode the PUCCH related to thebundled information). The bundling operation may be performed relativeto the transport blocks received in the TDD carrier; the bundledACK/NACKs may be sent over the FDD carriers. The bundled ACK/NACK may besent over the TDD (e.g., supplementary carrier). In a combined TDD/FDDdesign, the ACK/NACK may be sent on the primary carrier and/or thesecondary carrier, e.g., based on Rel-10 rules. For example, theACK/NACK may be sent on the secondary carrier if a PUSCH has beenallocated on the secondary carrier, and no PUSCH has been allocated onthe primary carrier.

For Carrier Aggregation, the PHICH may be transmitted on the DL carrierthat was used to transmit the UL grant. The timing of responses that maybe expected on the PHICH may differ in FDD and TDD. For FDD, the DLACK/NACK may be sent four subframes after the UL transmission. In TDD,this timing may be variable (e.g., when the DL ACK/NACK may be sent maynot be fixed, for example, the number of subframes after the ULtransmission when the DL ACK/NACK may be sent may not be fixed). Themapping of the PHICH resources may differ for FDD and TDD. In FDD, eachframe may have the same number of PHICH resource elements in the firstOFDM symbol. In TDD, the number of the PHICH resources may depend on thesubframe. In TDD, the size of the PHICH resources may be adjusted basedon the UL/DL configuration (e.g., a UL-heavy configuration may have moreresource elements allocated to the PHICH). PHICH collisions may beconsidered (e.g., may be limited to consideration) for the case ofcross-carrier scheduling and may be resolved by a Demodulation ReferenceSignal (DMRS) cyclic shift mechanism.

The joint TDD/FDD approach may send the PHICH on the supplementary TDDcarrier, e.g., to make use of the adjustable PHICH resources availableon this carrier.

Some DCI Formats on the PDCCH may be different between TDD and FDD (e.g.the DCI format 1 may be three bits for the Hybrid Automatic RepeatRequest (Hybrid ARQ or HARQ) process and two bit DAI for FDD; and it maybe four bits for HARQ process and no DAI for TDD. If cross carrierscheduling is being used on the primary carrier, a PDCCH search spacemay be created and allocated to decode TDD and FDD DCI formats that maybe separate from the FDD PDCCH search space. This may simplify blinddecoding of the PDCCH.

The UL grants may be signaled by the PDCCH using DCI format 0. In FDD,the UL grant may start four subframes after the DCI format 0 is received(e.g., the DCI format 0 may also be different for TDD and FDD). In TDD,the UL index in DCI format 0 may specify the timing of the UL grant. Inorder to perform cross-carrier scheduling in the UL with a DSSsupplementary TDD carrier, a TDD DCI format 0 may be created and usedfor alignment with the FDD DCI format. The information from the DCI senton the FDD carrier may specify (e.g., indicate) whether the UL grant maybe specific to the FDD or TDD carrier, and/or when it may be scheduledif it is indicated to be specific to the TDD carrier.

To support DL heavy Carrier Aggregation (CA) configurations, PUCCHformat 3, may allow a larger number of bits for the ACK/NACK (e.g., whenformat 1b with channel selection may not have sufficient bits for theACK (e.g., the used ACK)). In FDD ten bits may be allocated in PUCCHformat 3. In TDD: twenty bits may be allocated in the PUCCH format 3.The ACK/NACK may be treated as a supplementary TDD carrier or as an FDDsupplementary carrier. ACK/NACK bundling may not be implemented as isthe case for TDD because there may be an UL FDD carrier active (e.g.,primary carrier).

CQI reporting may be modified. If a TDD carrier is used, the way inwhich system information (SI) is interpreted for CQI reporting may bedifferent for the TDD or FDD carrier. A separate SI may be used for FDDand TDD carriers. Mixing TDD and FDD may be more complex for thescheduler. The scheduler may be able to handle (e.g., use) two differentschedules of TDD and FDD to come up with the DL allocation decisions.The upper layer event reporting and measurements may be modified givendifferent timing for CQI reports coming from the TDD and FDD carrier.

Coexistence may be implemented. Spectrum sharing among secondary usersmay comprise an effective use of the DSS bands. If it is not coordinatedwell, the DSS bands may be left unoccupied, which may result in a wasteof frequency bands, or heavily accessed by secondary users, e.g.,causing significant interference to each other. A coexistence mechanismmay be desirable. It may enable an effective usage of the DSS bands andmay improve the communication quality of the secondary networks.Opportunistic access to DSS bands may be disclosed herein.

A database enabled coexistence solution may be used. A network mayinclude a Coexistence Manager and Policy Engine that may be used tocoordinate opportunistic use of DSS bands with other secondaryusers/networks. The Coexistence Manager of a given network may includeinterfaces to the TVWS/Coexistence databases, network devices,Coexistence Managers of other networks, etc. Location based DSS bandallocations may be distributed to eNBs/HeNBs or centralized at the CN.The Policy Engine may generate and enforce polices based on databaseinformation and/or rules (e.g., operator defined rules). Centralizedhierarchical coexistence database management may be used. For example, alocal database, which may be CN based, may be used to coordinatesecondary usage within a given operators network, while an Internetbased database may be used to coordinate secondary usage with externalusers/networks.

A distributed approach may be used, e.g., in which no centralized entitymay exist to make spectrum allocation decisions. In this approach, theeNB/HeNB may be responsible for accessing the coexistence database,processing the spectrum sharing negotiation with neighbor eNB/HeNBs, andmaking spectrum allocation decisions.

A spectrum sensing coexistence solution may be implemented. The networkmay rely on spectrum sensing results to coexist with other secondarynetworks. In this approach, an entity at the eNB/HeNB may negotiateaccess to DSS bands. This entity may exchange sensing and/or channeloccupancy information with neighboring eNBs/HeNBs. A centralizedapproach based on spectrum sensing may be used. A central entity in theCN may process the spectrum sensing results received from the HeNBs/eNBsand may make decisions about eNB/HeNB channel assignments.

Contention based coexistence may also be implemented. Carrier sensingmay be performed for Clear Channel Assessment (CCA) prior to commencingwith transmissions. The eNB may maintain control of grant and schedulingof transmission opportunities. Transmissions may be “gated” by the CCA.

FIG. 7 is a diagram that illustrates exemplary inter-band and inter-bandcarrier aggregation (CA). Referring to FIG. 7, in LTE-A, two or more(e.g., up to 5) component carriers (CCs) may be aggregated to supportwider transmission bandwidths, e.g., bandwidths of up to about 100 MHz.A UE (e.g., UE 102 a), depending on its capabilities, may simultaneouslyreceive and/or transmit on one or more CCs. The UE may be capable ofaggregating a first number of differently sized CCs in the uplink (UL)and/or the same or a different number of such CCs in the downlink (DL).The CA may be supported for both contiguous and non-contiguous CCs.Exemplary scenarios may include one or more of the following as shown inFIG. 7: (1) intra-band contiguous CA in which CCs on a single band(e.g., frequency Band x) may be aggregated such that, for example,multiple adjacent CCs produce a contiguous bandwidth wider than 20 MHz;(2) intra-band non-contiguous CA in which CCs on a single band (e.g.,frequency Band x) may be aggregated such that, for example, multipleadjacent CCs and at least one non-adjacent CC of the same band areaggregated to produce a non-contiguous bandwidth and may be used in anon-contiguous manner; and (3) inter-band non-contiguous CA in which CCsof different bands (e.g., frequency Bands x and y) may be aggregated.

One or more Primary Carriers (PrimCs) may be supplemented with one ormore Supplementary Carriers (SuppCs or Supplementary Cells or SuppCells)in the DSS bands. A SuppC may be used in an opportunistic fashion in theDSS bands to increase bandwidth (e.g., dynamically increase bandwidth)using advanced CA to provide, for example, hot-spot coverage. Aheterogeneous network architecture may include a macrocell that mayprovide service continuity and a pico/femto/RRH cell that may aggregatethe licensed and DSS bands to provide increased bandwidth associatedwith the hot spot.

In an FDD system operating in the licensed band with an FDD PrimC, theSuppC in the DSS band may use FDD or TDD. Use of TDD in the DSS bandsmay provide one or more of the following: (1) TDD may use (e.g., may belimited to) one frequency channel or band, so, it may be simpler toidentify (e.g., find) a single suitable DSS frequency channel, e.g., asopposed to finding, for example, a pair of separated frequency channelsfor UL and DL; (2) with two frequency channels that may be used by FDD,there may be more chances to interfere with incumbent users on one ormore of the channels than TDD and the single channel configuration; (3)detection of incumbent users on a single frequency channel for TDD maybe easier than for two channels associated with FDD; and (4) allowingasymmetric DL/UL data connection on a single frequency channel mayenable a dynamic spectrum assignment system where channel bandwidth maybe optimized.

Although FDD may use two channels or bands, it may be possible to useFDD in a single channel by splitting the channel or by using a singlechannel in one of an UL mode or a DL mode. These modes may be switcheddynamically over time, e.g., to enable changes to bandwidth for both theUL and the DL. For example, a dynamic FDD system in the DSS bands mayenable a SuppCell that may be configured dynamically to be one of a DLcell or an UP cell, or, switch at predefined times between UL and DL.TDD and dynamic FDD Supplementary Carriers may be described herein.

The Physical Hybrid ARQ Indicator Channel (PHICH) may be used fortransmission of Hybrid ARQ acknowledgements (ACK/NACK) in response toUL-Shared Channel (SCH) transmissions. Since hybrid ARQ may use areliable transmission for the PHICH, the error rate of the PHICH may beestablished to be at or below a threshold (e.g., at or below 0.1% ACK orNACK misdetections).

The PHICH may be transmitted by the eNB on specific resource elementsthat may be reserved for the PHICH transmission. Depending on the SIthat may be transmitted in, for example, the Master Information Block(MIB), the PHICH may occupy resource elements in the PDCCH, for example,in the first OFDM symbol of a subframe (e.g., for a normal PHICHduration), or in the first 2 or 3 OFDM symbols of the subframe (e.g.,for an extended PHICH duration)). The MIB may specify how much of the DLresources may be reserved for the PHICH through the PHICH-resourceparameter.

FIG. 8 is a diagram that illustrates an exemplary Physical Hybrid ARQIndicator Channel (PHICH) group modulation and mapping. Referring toFIG. 8, the PHICH group modulator 800 may include a plurality ofrepetition units 810A . . . 810N (e.g., 3× repetition units), aplurality of modulators 820A . . . 820N (e.g., BPSK or QPSK or othermodulators, among others), a plurality of orthogonal code multiplexers830A . . . 830N, a summing unit 840 and a scrambling multiplexer 850. Aplurality of ACK/NACKs may be input to the PHICH group modulator 800.Each ACK/NACK may be separately processed via, for example, a series ofthe repetition unit 810A, the modulator 820A, and the orthogonal codemultiplexer 830A. The output of each orthogonal code multiplexer 830A .. . 830N may be summing via the summer unit 840 and multiplexed byscrambling multiplexer 850 using a scrambling code.

The PHICH group modulator 800 may use orthogonal sequences or codes asinputs to each of orthogonal code multiplexers 830A . . . 830N, e.g., tomultiplex multiple PHICHs onto the same set of resource elements. Forexample, any number (e.g., 8 PHICHs) may be transmitted over the sameresource element. These PHICHs may be collectively referred to as aPHICH group, and the separate PHICHs within a group may be distinguishedusing the orthogonal code used during modulation of the PHICH.

Each PHICH group may generate, for example, a total of 12 symbols or adifferent number of predetermined symbols, which may be sent over anynumber of resource groups (e.g., 3 resource element groups) that may bespread in frequency, e.g., to ensure good frequency diversity. The cellID may be used to distinguish the location of this mapping in thefrequency range.

Based on the mapping, a PHICH resource (e.g., assigned to or allocatedfor sending the ACK/NACK to a UE) may be identified by an index pair(e.g., n_group, n_seq), where n_group may be the PHICH group number, andn_seq may be the orthogonal sequence that may be used to distinguishPHICH resources within a group. The amount of resources assigned to thePHICH within a subframe may be determined by the number of PHICH groupsand may depend on whether TDD or FDD is used. For FDD, the number ofPHICH groups may be fixed in each subframe and may be defined byEquation 1:

$\begin{matrix}{N_{PHICH}^{group} = \left\{ \begin{matrix}\left\lceil {N_{g}\left( {N_{RB}^{DL}/8} \right)} \right\rceil & {{for}\mspace{14mu} {normal}\mspace{14mu} {cyclic}\mspace{14mu} {prefix}} \\{2 \cdot \left\lceil {N_{g}\left( {N_{RB}^{DL}/8} \right)} \right\rceil} & {{for}\mspace{14mu} {extended}\mspace{14mu} {cyclic}\mspace{14mu} {prefix}}\end{matrix} \right.} & (1)\end{matrix}$

where N_(g) ε{⅙, ½, 1, 2} represents the PHICH-resource parameter in theMIB. For instance, in subframes that may be reserved for the UL, thenumber of PHICH groups may be zero.

For TDD, the above equation for the number of PHICH groups may befurther multiplied by a factor m in each subframe, where m is given byTable 1 below:

TABLE 1 Uplink-downlink Subframe number i configuration 0 1 2 3 4 5 6 78 9 0 2 1 — — — 2 1 — — — 1 0 1 — — 1 0 1 — — 1 2 0 0 — 1 0 0 0 — 1 0 31 0 — — — 0 0 0 1 1 4 0 0 — — 0 0 0 0 1 1 5 0 0 — 0 0 0 0 0 1 0 6 1 1 —— — 1 1 — — 1

The UL and DL configuration may be set forth by the EuropeanTelecommunications Standards Institute (ETSI) in the standardpublication “Evolved Universal Terrestrial Radio Access (E-UTRA)Physical layer procedures (3GPP TS 36.213 version 10.0.01 Release 10(Rel-10) published in January, 2011, the contents of which areincorporated by reference herein.

The PHICH allocations may occur on a per-UE basis, e.g., at the time ofthe UL grant reception, using Equation 2 for the PHICH resource mapping:

n _(PHICH) ^(group)=(I _(PRB) _(_) _(RA) +n _(DMRS))mod N _(PHICH)^(group) +I _(PHICH) N _(PHICH) ^(group)

n _(PHICH) ^(seq)(└I _(PRB) _(_) _(RA) /N _(PHICH) ^(group) ┘+n_(DMRS))mod 2N _(SF) ^(PHICH)  (2)

The uplink grant for a subframe may include the PHICH group number andorthogonal sequence number or code for the PHICH assigned to the UE,that may be specified by the lowest PRB index of the UL grant (I_(PRB)_(_) _(RA)) and the cyclic shift that may be used when transmitting theDemodulation Reference Signal (DMRS) to distinguish between differentusers employing MU-MIMO (n_(DMRS)). In terms of the time relationship,the PHICH may be located in subframe n+k, where n is the subframe inwhich the UL transmission may be made on the PUSCH. For FDD, k may befixed at a predefined number of subframes (e.g., 4 subframes), whereasin TDD, k may depend on the UL/DL configuration and may be determined bya table lookup, for example.

In Rel-8, the group and sequence index allocation specified by Equation2 above may be sufficient to guarantee that each UE is assigned a uniquePHICH resource for each UL transmission. Since the DMRS value mayalready be used to distinguish between terminals employing MU-MIMO, itmay inherently distinguish between PHICH resources when two terminalsmay be allocated resources starting at the same PRB on the samesubframe.

When CA is allowed, transmissions from UL carriers may be independentand the potential may exist for two terminals to use the same I_(PRB)_(_) _(RA) and DMRS cyclic shift in the same subframe on a different CCfor a UL transmission. Although, the possibility of PHICH collisions mayexist, the scheduler may be designed to avoid such collisions. One ormore of the following may apply: (1) the PHICH may be transmitted on thesame component carrier that was used to transmit the UL grant, which mayreduce the number of combinations considered when analyzing the PHICHcollisions, e.g., since a given component carrier may be responsible forthe PHICH for the terminals in which it transmitted the grant (DCIformat 0); (2) the UL heavy configurations, for example, configurationswhere there are more UL carriers than DL carriers, may not need to beconsidered; the scheduler may, in theory, allocate sufficient PHICHresources on x DL component carriers used for y UL component carrierswhen x>=y and when the UL heavy configurations are considered, thenumber of PHICH resources per UL component carrier may be reduced; (3)the DMRS may be used as a mechanism for avoiding the PHICH collisionsthat may occur from cross-carrier scheduling (e.g., when the schedulerdecides to allocate the same starting PRB to two different terminals inthe same subframe, it may ensure that it assigns a different DMRS toeach of the terminals); and (4) for semi-persistent scheduling (SPS)which may use a DMRS index of 0, having SPS transmissions occur on theprimary component carrier may ensure that no PHICH collisions occur as aresult of the SPS.

When a TDD SuppC is added in the DSS bands, it may or may not beequipped with a DL PHY layer control channel (e.g., a PDCCH and/or aPHICH, etc.). Since the DSS bands may be evacuated due to the presenceof a primary user (e.g., TVWS) or may be shared with other DSS users,control information may be transmitted on the licensed cells by a system(e.g., LTE system) to aggregate the licensed and DSS bands.

The use of a TDD SuppC may result in an overall configuration of thesystem that may be UL heavy (e.g., PHICH resources for the ULtransmissions on the SuppCells are made over the cells in the licensedband). The introduction of a supplementary TDD carrier, which may not beconfigured with PHICH resources (e.g., to maintain the PHICH on thelicensed band) may cause control issues, e.g., for Rel-10 devices usingTVWS, which may be due to additional PHICH resources. For example, anLTE system may lack an appropriate number of PHICH resources on thelicensed carrier to aggregate SuppC DSS bands. As the number ofsupplementary TDD carriers (e.g., using the PHICH provided in thelicensed FDD carriers) increases, the PHICH resources on the FDD carriermay be shared by a greater number of UL carriers. PHICH resources mayneed to be added, e.g., beyond those supplied in Rel-10. This may be dueat least in part because of one or more of the following: thepower-limited nature of the PHICH; the number of PHICH resourcesbecoming more scarce; and additional strain being placed on thescheduler.

The aggregation of a supplementary TDD carrier with a system operatingin the licensed band in FDD mode may require resolving how to use thevarious PHICH resources efficiently. For example, one or more of thefollowing may apply: the number of PHICH resources used for TDD maychange from one subframe to the next based on the TDD UL/DLconfiguration (e.g., the dependence of the number of PHICH groups on thesubframe for TDD), but the number of PHICH groups in an FDD subcarriermay be fixed on a subframe-by-subframe basis; and, the timing of thePHICH association with the corresponding UL transmission in TDD maydiffer from that given in FDD. Implementations for associating the PHICHresources for a given UL transmission may be disclosed.

Systems, methods, and instrumentalities are disclosed to providefeedback to a user equipment (UE). A UE may transmit uplink data via asupplementary cell. A network device, such as a HeNB, eNB, etc., mayreceive the uplink data from the UE via the supplementary cell. Thenetwork device may send feedback associated with the uplink data to theUE via a physical downlink shared channel (PDSCH) when downlink data isavailable for transmission to the UE. The feedback may be physicalhybrid ARQ indicator channel (PHICH) ACK/NACK information. ACK/NACKinformation may be referred to as ACK/NACK (e.g., sending ACK/NACKinformation for an UL transmission may be referred to as sendingACK/NACK for the UL transmission). The feedback sent via the PDSCH maybe multiplexed with the downlink data. The network device may send thefeedback associated with the uplink data to the UE via a physicaldownlink control channel (PDCCH) when downlink data is not available fortransmission to the UE. The feedback may be sent on one or more of aprimary component carrier and a secondary component carrier. Thefeedback may be sent on a best available licensed cell. The feedback maybe sent on a supplementary cell.

The feedback sent via the PDCCH may be sent via a downlink controlinformation (DCI) format on the PDCCH. The DCI format may be format 1Cassociated with the PDCCH. A modulation and encoding value associatedwith the DCI format may be used to indicate that the DCI formatcomprises ACK/NACK information. ACK/NACK information associated with thefeedback may be sent in a resource block assignment. The resource blockassignment may be a single resource block using a type 2 allocation.

Systems, methods, and instrumentalities may be disclosed for increasingthe amount of PHICH resources available, e.g., in an LTE system, thatmay accommodate a need for additional PHICH resources (e.g., beyondthose defined in Rel-10) for sending feedback (e.g., ACK/NACKinformation) in the DL. Backward compatibility may be included.

Implementations may be disclosed for increasing the amount of PHICHresources available and defined in LTE Rel-10, e.g., to leverageadditional resources for sending ACK/NACK for UL transmission on theSuppCs. However, the disclosed systems, methods, and instrumentalitiesare not limited thereto and may be implemented in other systems.

ACK/NACK may need to be provided for UL transmissions on the SuppC(s).The licensed band carrier (e.g., PCC or SCC) may be used to send theACK/NACK for the supplementary carrier transmission(s) and additionalresources may be defined and leveraged for this purpose. A HeNB mayprovide a connection for UEs that do not make use of the DSS bands(e.g., and whose operation may be limited to Rel-10).

In addition to an increase in the number of PHICH resources on thelicensed CCs in order to satisfy PHICH uses, when SuppCs are introduced,the PHICH resources that may be defined on the SuppCs may be used. Theseresources may be defined according to Rel-8 PHICH definitions for TDD.

Carrier aggregation of supplementary carriers operating in the DSS bandsmay be disclosed. However, the disclosed systems, methods, andinstrumentalities are not limited thereto. As an illustration,increasing the number of PHICH resources may be used in other scenarios.For example, additional component carriers (e.g., a carrier limited touplink transmission) may be introduced into a licensed band and maycreate uplink heavy configurations (e.g., more uplink component carriersthan downlink component carriers) and may result in a PHICH shortagewith respect to the number of PHICH resources available, e.g., inRel-10. Implementations such as those disclosed herein may be used toincrease the number of PHICH resources to address a PHICH shortage(e.g., the addition of TDD or FDD carriers in the licensed band that maycreate PHICH resource shortages).

Increasing the number of PHICH resources on the licensed carrier may bedisclosed, which may include one or more of the following: creation ofadditional PHICH resources in the PDCCH of the licensed carrier;creation of a distinct channel on the licensed band for PHICH used bythe SuppC; and, multiplexing of the PHICH with data allocations of thedata space or resources (e.g., the PDSCH).

PHICH resources for the supplementary carrier may be present on thesupplementary carrier, e.g., as disclosed herein.

Implementations may be disclosed where the SuppC may use TDD framestructure and timing. Such implementations may be applied for an FDDSuppC.

FIG. 9 illustrates an exemplary PHICH resource allocation 900 associatedwith addition of a supplementary carrier or re-configuration of anexisting supplementary carrier. PHICH resource allocation 900 mayincrease the number of PHICH resources, e.g., by increasing the numberof PHICH groups. Rel-10 may include the transmission of a value N_(g)via the MIB to set the number of PHICH groups for Rel-10 devices. Themaximum value for N_(g) in Rel-10 is 2. Backward compatibility may belost if this maximum value is increased, e.g., Rel-10 devices may notoperate properly. A value N_(g)′ may be implemented for beyond Rel-10devices that may enable additional PHICH resources to be defined. Thevalue of N_(g)′ may be known by UEs that support the DSS band usage andmay not be known by other devices (e.g., which may provide backwardcompatibility). The value N_(g)′ may not be transmitted in the MIB. Thevalue of Ng′ may be sent through an RRC message, e.g., specific to theDSS users. It may also be part of the reconfiguration message, which mayadd or remove a supplementary carrier, or change the UL/DLconfiguration.

Since the burden of the PHICH resources used for the UL transmissions onthe supplementary TDD carrier may be absorbed by the licensed FDDcarrier, N_(g)′ may be increased each time a supplementary TDD carrieris added, or when the supplementary TDD carrier is reconfigured so thatthe UL subframes in the configuration may be increased. N_(g)′ may bedecreased when a supplementary TDD carrier is removed from theaggregation, or the supplementary TDD carrier is reconfigured so thatmore DL subframes are added in the TDD configuration. Since each of thelicensed band CCs (e.g., primary or secondary CCs) may have its ownvalue of N_(g)′, increases in the value of N_(g)′ followingsupplementary TDD carrier addition or reconfiguration may be appliedindividually to each licensed band CC and may be at the discretion ofthe eNB/HeNB.

In FIG. 9, the licensed DL CCs may include primary CC 910 and secondaryCC 920. Because the value of N_(g) (e.g., which may equal 2) in thiscase may not exceed its maximum value, the procedure may operate in amanner related to Rel-10. N_(g)′ may be detected by beyond Rel-10devices but additional action may not be taken by the Rel-10 devices.When a supplementary TDD CC 930 is added, N_(g)′ of the primary CC 910may be increased to 3. Because N_(g)′ may be sent, for example, via RRCmessaging, Rel-10 and prior devices may not take action, andbeyond-Rel-10 devices may detect N_(g)′ and begin to look for a PHICHgroup associated with the supplementary CC 930, for example, in thecontrol information region (e.g., symbols 0-2) of each subframe orrespective subframes.

When the supplementary TDD CC 930 changes UL/DL configuration such thatit is more UL heavy, the N_(g)′ of the primary CC 910 may be increasedto 4, e.g., to create one or more additional PHICH groups associatedwith the supplementary TDD CC 930.

Changes to the UL/DL configuration such that the supplementary TDD CC930 is less UL heavy may cause the N_(g)′ to decrease removing one ormore of the additional PHICH groups associated with the supplementaryTDD CC 930.

For backward compatibility, e.g., for Rel-8 and Rel-10 UEs, the PHICHresources created by increasing from N_(g)′=2 to N_(g)′=3 (for instance)may be limited to UEs using the DSS bands (e.g., for ACK/NACK sent onthe SuppC). Equation 2 may be modified or may be adapted todifferentiate the additional resources defined with N_(g)′>2 to thosedefined with N_(g)′<=2. For example, this mapping may use a separatevalue of N_(g) for UEs that use the DSS bands and may include one ormore of the following. In a first case, if N_(g)=2 or less is sufficientto allocate the PHICH resources for the current CA scenario (e.g.,including the SuppC), the PHICH mapping may use the Rel-10 procedure todefine the PHICH resources for the SuppC or set N_(g)′=N_(g). In asecond case, if N_(g)=2 is not sufficient, the number of PHICH groupsallocated by the eNB/HeNB may be increased by using N_(g)′>N_(g) andtheir location in frequency may be chosen among the remaining ControlChannel Elements (CCEs) not used for the PHICH or the PCFICH. In thesecond case, signaling of N_(g)′ may be limited to UEs that may becapable of using the DSS bands, e.g., using RRC signaling. A mapping maybe created, relative to these new resources, for these users. In orderfor minimal impact of the licensed users (e.g., in terms of CCEblocking), this mapping may ensure that the UE specific search spacesassociated with a particular aggregation level may not each be renderedunusable by the presence of the additional PHICH resources. A size limiton the size of N_(g)′ may be set, e.g., so that UEs may not be adverselyaffected by the mapping. UEs limited to Rel-8 and Rel-10 may use thePHICH resources on the licensed CCs that had been defined with N_(g)=2or less.

By increasing N_(g)′, the control space or resources available forresource allocations to Rel-8 and Rel-10 UEs may decrease. Due to theimpact of increasing N_(g)′ on the availability of search space forlegacy LTE and LTE-A users, the values that N_(g)′ may take on, or thealgorithm for defining the number of DSS user specific PHICH resourcesmay provide finer granularity of additional PHICH resources thanEquation 1. For instance, in Equation 1, an increase by 1 of the valueof N_(g)′ may not cause the number of PHICH groups to increase by N_(DL)^(RB)/8, but rather by a small number of PHICH groups. N_(g)′ may takeon decimal values in Equation 1 (e.g., N_(g)′=2.1). This may allow anincrease in the number of PHICH resources available on the licensed bandwithout quickly depleting the PDCCH resources.

FIG. 10 illustrates exemplary PHICH resource allocation 1000 usinglinked reserved control channel elements (CCEs). The PHICH resourceallocation 1000 may be enabled using static linking of SuppC 1-3 toreserved CCEs. The number of PHICH resources may be increased by the useof reserved CCEs. For example, CCEs may be reserved for use as PHICHresources. A mechanism for semi-static linking may be used to controlthe number and/or the size and the location of reserved CCEs that may becreated in the PDCCH of each licensed carrier for static linking.

In Rel-8 and Rel-10, each aggregation level in the UE specific searchspace may have at least 2 and sometime more PDCCH candidates. Thereserved CCEs for the supplementary PHICH may be allocated such that areserved CCE may not impact (e.g., affect) more than one PDCCH candidateper aggregation level (e.g., for L=4 or L=8, etc.). The reserved CCElocation for the supplementary PHICH may change in function based on theframe number, e.g., as in the case for the UE specific search spaces.This may allow for the reserved CCEs to be defined (e.g., allocated)without elimination of the UE specific search spaces at a givenaggregation level. For instance, for a given UE, the reserved CCEs mayeliminate at most one of the UE specific search spaces at aggregationlevel 8, so that a PDCCH candidate may exist at this aggregation levelfor this UE. A reservation equation for the reserved CCEs, based on theabove, may be developed.

In an illustration, the number of PDCCH candidates for different searchspaces aggregation levels and sizes is illustrated in Table 2 for UESpecific and Common types of search spaces. For example, the number ofPDCCH candidates may decrease with increasing aggregation level.

TABLE 2 Number of Search space PDCCH Type Aggregation level Size [inCCEs] candidates UE- 1 6 6 specific 2 12 6 4 8 2 8 16 2 Common 4 16 4 816 2

The number of PHICH resources may be increased dynamically to take intoaccount the variations on the PHICH resource used for a given subframebased on the UL/DL configuration of the TDD SuppC. In such cases,additional PHICH resources may be assigned only to subframes where theseare needed. The reserved CCEs may be used for PHICH resources for ULtransmissions on the supplementary carrier. Subframe variations of thePHICH resources may follow the UL/DL configuration of the TDD SuppC. Forexample, a subframe in which an ACK/NACK traditionally cannot be sent inTDD (e.g., because it may be configured as UL) may not have reservedCCEs defined.

An example may be to allocate a plurality of PHICH groups (e.g., 3 PHICHgroups) in each reserved CCE. Assignment of the unused reserved CCEs maybe inefficient. A minimum level of such assignments may be enabled(e.g., because after assigning a resource element of a given CCE to aPHICH resource, it may not be reassigned to a PDCCH for some operationalperiod, for example, until it can be removed). In order to design thePHICH allocation for a system using SuppCs and making use of reservedCCEs, one or more of the following may be addressed and/or determined:the number of additional PHICH groups that may be introduced (e.g., persubframe, based on the TDD configuration, which may determine the numberof CCEs that may be reserved for each subframe, on each licensed bandcarrier); and, the mapping of the PHICH channels created by the reservedCCEs to each UE based on the UL grant.

By using semi-static linking between licensed carriers and supplementaryTDD carriers, regardless of the number of SCCs, each supplementary TDDcarrier may be linked to a licensed band carrier (e.g., the PCC or theSCC) and a licensed band carrier may have a link to one or moresupplementary TDD carriers. In this way, the reserved CCEs for eachlicensed carrier may be fixed based on the TDD UL/DL configuration ofeach of the supplementary TDD carriers that the PCC or the SCC may belinked to. The UE may know which licensed CC may be sending the PHICH,as the UL grants for traffic on the supplementary carrier may be sent bythe linked licensed carrier. The PHICH resources may be shown as aconceptual block within the component carrier to demonstrate staticlinking. The actual size of each Supp PHICH may change on a per-subframebasis to follow the UL/DL configuration of the SuppCs.

In FIG. 10, a primary DL CC or PCC 1010 and a Secondary DL CC or SCC1020 may be FDD component carriers that may be present in the licensedband. The PCC 1010 may be semi-statically linked to supplementary TDD CC1030 in the DSS band and the SCC 1020 may be semi-statically linked totwo supplementary TDD carriers 1040 and 1050 in the DSS bands. Thelinking may be established or modified using RRC signaling (e.g., viaRRC message) or using MAC CE messages. Responsive to or after thelinking is established, the number of PHICH groups created throughreserved CCEs may be determined, e.g., based on the linkages. When theUL/DL configuration of one of the supplementary TDD carriers changes,for example the supplementary TDD carrier 1050 does not use any ULresources, the number of PHICH groups in one of the licensed bandcarriers (e.g., the CCEs 1026 associated with, the PHICH resourcesallocated to supplementary TDD carrier 1050) based on linking may change(e.g., may be removed or reduced), which may be automatic.

The PCC 1010 may include a PDCCH 1012 for control information includinga reserved CCE area 1014 that may be semi-statically linked to thesupplementary TTD CC 1030 and the SCC 1020 may include a PDCCH 1022 forcontrol information including a first reserved CCE area 1024 that may besemi-statically linked to the supplementary TTD CC 1040 and a secondreserved CCE area 1026 that may be semi-statically linked to thesupplementary TTD CC 1050 such that the CCE areas 1014, 1024, and 1026may be reserved areas used (e.g., exclusively) for linked PHICHresources for ACK/NACKs. The PHICH resources for the ACK/NACK for ULtransmission in the licensed bands may be reserved, e.g., based onRel-8/Rel-10 mechanisms. Since UL heavy configurations in the licensedband may not be allowed, these resources may be sufficient for licensedband UL transmission and the ACK/NACK.

The reserved CCEs may be used in the PCC or SCC for each supplementarycarrier linked to a licensed carrier such that a set of reserved CCEsmay be associated to each supplementary carrier. The size of thatreserved CCE set 1014, 1024 or 1026 may be determined based on the UL/DLconfiguration and bandwidth of the supplementary TDD carrier 1030, 1040,or 1050 associated with the respective set 1014, 1024, or 1026. When thesupplementary carrier (e.g., supplementary carrier 1050) is removed fromthe aggregation scenario, the associated (e.g., linked) reserved CCE set1026 may be removed from the corresponding linked licensed band CC.

Linking may be changed, e.g., in order to redistribute the number ofreserved CCE sets per licensed band component carrier when supplementarycarriers are removed from the aggregation scheme.

Allocation of the SuppC PHICH resources may include one or more of thefollowing. The addition or removal of a reserved CCE and/or linking of asupplementary TDD carrier to a PCC or SCC may be done at the time inwhich the supplementary TDD carrier is added, removed, or reconfigured.If the addition or activation of a supplementary TDD carrier is donethrough an RRC message, the RRC message may configure (e.g., for the UEsthat may use the supplementary carrier) the linked licensed band carrier(e.g., including the location and/or the size of the reserved CCEs).This may be the case for an activation message or supplementary carrieraddition which may be sent by a MAC CE (e.g., the MAC CE may include thelinking information and/or the reserved CCE size or location). Areconfiguration of the UL/DL TDD configuration or the supplementary TDDcarrier bandwidth may be associated with a change in the reserved CCEconfiguration.

This procedure may be optimized to reduce the size of thereconfiguration message by having the size and location of the reservedCCEs be tied (e.g., implicitly) to the configured supplementary TDDcarrier such that a specific bandwidth and UL/DL configuration for asupplementary TDD carrier may implicitly define, e.g., based onformulas, the location of the reserved CCEs and the size of the CCEsbeing reserved. The mapping may define the number of CCEs per subframe.The additional PHICH resources used per supplementary TDD carrier maychange on a per subframe basis. It may be beneficial to have reservedCCEs removed when a supplementary carrier is deactivated or removed(e.g., it may allow the reserved CCEs to be used as CCEs for PDCCH). Thescheduler may treat these reserved CCEs as statically defined (e.g.,based on the maximum number of supplementary TDD resources) and use themlimited to the case when appropriate based on the number ofsupplementary TDD carriers present.

Each reserved CCE set may handle the ACK/NACK for UL transmissions on asingle supplementary TDD carrier. Equation 1 and Table 1 may be used todetermine the number of PHICH groups and/or reserved CCEs in a set on aper subframe basis. This may be accomplished for each reserved CCE setwithin a CC and may allow the eNB/HeNB to make use of more CCEs forPDCCH during subframes in which PHICH may not be transmitted. Lessreserved CCEs may be used. The reserved CCEs may be distributed acrossthe bandwidth of the licensed FDD CC, e.g., in order to ensure frequencydiversity.

After a mapping of reserved CCEs, which may include PHICH resourcemapping within those reserved CCEs, is established for UEs (e.g., eachUE) to follow, equations similar to Equation 2 may be derived to assignPHICH resources to each UE based on the PRB index and the DMRS cyclicshift index provided by the UL grants. The derived equations may makeuse of the reserved CCEs.

FIG. 11 illustrates an exemplary PHICH resource allocation 1100 usingreserved CCEs. A PCC 1110 and a SCC 1120 may be FDD component carriersthat may be present in the licensed band. The PCC 1110 and the SCC 1120may be jointly linked to supplementary TDD CCs 1140, 1150 and 1160 inthe DSS bands via reserved CCEs 1130A and 1130B. The reserved CCEs 1130Aand 1130B may be pooled and used for the PHICH resources for thesupplementary TDD CCs collectively. The joint linking may be establishedor modified using RRC signaling (e.g., via a RRC message) or using MACCE messages. Responsive to or after the linking is established, thenumber of PHICH groups created through reserved CCEs may be determinedbased on the linkages. When the UL/DL configuration of one of thesupplementary TDD carriers changes (e.g., when the supplementary TDDcarrier 1050 does not use UL resources), the number of PHICH groups inthe licensed band carriers (e.g., the CCEs 1030A and/or 1030B) maychange (e.g., may be removed or reduced), which may be automatic.

The PCC 1110 may include a PDCCH 1112 for control information includinga reserved CCE area 1130A and the SCC 1120 may include a PDCCH 1122 forcontrol information including a reserved CCE area 1130B. For example,the reserved CCE areas 1130A and 1130B may collectively or jointly belinked to each of the supplementary TDD CCs 1140, 1150, and/or 1160 suchthat the CCE areas 1130A and 1130B may be reserved areas used (e.g.,exclusively) for linked PHICH resources for the ACK/NACKs.

By way of example, reserved CCEs may be used to define the availablePHICH resources for Supp Cells as the sum of available PHICH groupsacross PCC and SCCs, e.g., to maximize trunking efficiencies. If 4 PHICHgroups may be available in a Primary Cell and another 4 PHICH groups maybe available in Secondary Cell, the total (e.g., collective) number ofavailable PHICH groups as used in Equation 2 (e.g., N_(PHICH) ^(group))may be set to 8.

Legacy UEs may be limited to detecting the original Licensed Band PHICHin one of the PDCCH areas 1112 or 1122, for example, of the PCC 1110 orSCC 1120. UEs that may use the DSS bands may detect the PHICH forLicensed Band in one of the PDCCH areas 1112 or 1122 of the PCC 1110 orSCC 1120 and the joint resources for the supplementary TDD cells 1140,1150, and 1160, e.g., which may be defined through reserved CCEs 1130Aand 1130B.

Mapping of the PHICH resources on the licensed band to the ULtransmissions on the supplementary carriers may include one or more ofthe following.

To avoid impacting legacy UEs (e.g., in terms of availability of PHICHresources) and to keep the scheduler complexity to a minimum, the jointPHICH resources for the supplementary TDD cells 1140, 1150, and 1160 maybe used by the DSS UE when they are performing UL transmissions on theDSS bands. When UL transmissions are performed by the DSS UEs on thelicensed bands, they may employ the PHICH resources for Licensed Bands(e.g., in the PDCCH 1112 or 1122), e.g., using rules related to Rel-10.

The reserved CCEs which make up the Joint PHICH resources for theSupplementary TDD Cells 1140, 1150, and 1160 may be defined continuouslyacross the licensed carrier 1110 and 1120 (e.g. using a single indexthat may take on values 0 to i₁ on the PCC and values i₁+1 to i₂ on theSCC). This may provide an equal trunking efficiency. UL allocations thatmay be made for the supplementary TDD carrier 1140, 1150 and 1160 (e.g.,whether scheduled from PDCCH on the supplementary carrier or from PDCCHon the licensed carrier) may use the one of the reserved CCEs 1130A or1130B based on an assigned index, e.g., regardless of where the UL granthas been made from. The index for the reserved CCE 1130A or 1130B to beused by a UE for a UL grant may be made implicitly from the starting PRBindex of the allocation and the DMRS. The assignment of the CCEs may bea function of the UE ID and the DMRS, e.g., to provide a better trunkingefficiency and not have the PHICH tied to the allocation (e.g., suchallocations on different supplementary carriers may likely have similarstarting UL PRBs). Different cyclic shifts assigned to each UE throughthe DMRS may be leveraged in order to differentiate between UEs that maybe assigned the same reserved CCE (e.g., due to them having the samestarting PRB for their UL allocation on different supplementarycarriers, or having cell IDs that have a modulo relationship to eachother based on the number of reserved CCEs).

An explicit mapping of reserved CCEs to UEs may be used to tie thereserved CCEs to each UE. This may use some signaling, which may be sentthrough RRC messaging, or in the DCI format 0 or 4 that may be used tosend the UL grant.

FIG. 12 illustrates an exemplary dynamic allocation 1200 of PHICHresources. The dynamic allocation 1200 may include a PCC 1210 and a SCC1220, which may be FDD component carriers that may be present in thelicensed band. The PCC 1210 and the SCC 1220 may link to supplementaryFDD CCs or SuppCells 1240 and 1250 in the DSS band via reserved CCEs1230A and 1230B. The reserved CCEs 1230A and 1230B may be staticallylinked or pooled and used for the PHICH resources for the supplementaryFDD CCs 1240 and 1250. The linking may be established or modified usingRRC signaling (e.g., via RRC messages) or using MAC CE messages.

The PCC 1210 may include a PDCCH 1212 for control information includingthe reserved CCE area 1230A and the SCC 1220 may include a PDCCH 1222for control information including the reserved CCE area 1230B.

In dynamic FDD, the SuppCells may operate as a cell limited to DL or asa cell limited to UL. When the SuppCell operates in the DL, no ACK/NACKfeedback in the DL may be required and no PHICH resources or a minimumset of PHICH resources may be allocated for Supp Cells 1240 and 1250, asillustrated by the X mark at the CCEs 1230A and 1230B for the DL modeperiod. When the SuppCells 1240 and 1250 operate in the UL mode period,ACK/NACK feedback may be provided. The SuppCell (e.g., being UL) mayreport the ACK/NACK feedback on another carrier (e.g., SuppCell 1240 mayreport the ACK/NACK feedback on the PCC 1210 and Supp Cell 1250 mayreport the ACK/NACK feedback on the SCC 1220.

The Supp Cell reconfiguration command may indicate information or a flagregarding changes of PHICH resources (e.g., the SuppCell 1240 changingfrom UL mode to DL mode or vice-versa). The switch in operating modesmay be pre-configured in advance and the transition time (e.g.,transition delay time) may be indicated. In this case, a transition fromUL mode to DL mode may signal (e.g., implicitly) to the UE that the SuppPHICH resources may be removed (e.g., to free up the CCE reservedresources for example 1230A or 1230B). The delay may be in the range of2 to 8 subframes and may be 4 subframes after the UL-to-DL transition,as shown in the FIG. 12. For a DL-to-UL transition, the previouslyallocated PHICH resources may be reallocated as in the previous cycle.

FIGS. 13, 14 and 15 illustrate exemplary allocation 1300 of PHICHresources of one of the component carriers. FIG. 13 illustrates a firstconfiguration 1300 of a licensed band (e.g. the Primary Cell or theSecondary Cell) in which no supplementary carrier (e.g., TDD or FDD) islinked to the licensed carrier. FIG. 14 illustrates a secondconfiguration 1400 of a licensed band (e.g. the Primary Cell or theSecondary Cell) in which a supplementary carrier (e.g., TDD or FDD) islinked to the licensed carrier. FIG. 15 illustrates a thirdconfiguration 1500 of a licensed band (e.g. the Primary Cell or theSecondary Cell) in which two supplementary carriers (e.g., TDD and/orFDD) are linked to the licensed carrier. In FIGS. 13-15, each subframe 1. . . N may include one or more of the following: a subframe controlarea or PDCCH 1310-1 . . . 1310-N; 1410-1 . . . 1410-N; or 1510-1 . . .1510-N; or a subframe data area or PDSCH 1320-1 . . . 1320-N; 1420-1 . .. 1420-N; or 1520-1 . . . 1520-N. The PDCCH of each subframe 1-N mayinclude a Physical Control Format Indicator Channel (PCFICH) 1330-1 . .. 1330-N; 1430-1 . . . 1430-N; or 1530-1 . . . 1530-N and the PHICH1340-1 . . . 1340-N; 1440-1 . . . 1440-N; or 1540-1 . . . 1540-N for thelicensed band. The PDSCH of each subframe 1-N may include one or morePHICHs according to the number of linked supplementary carriers (e.g.TDD and/or FDD carriers). For example, subframe 1 of FIG. 13 may have noPHICH in the PDSCH 1320-1, subframe 1 of FIG. 14 may have a PHICH 1450-1in the PDSCH 1420-1 and subframe 1 of FIG. 15 may have two PHICHs 1550-1and 1560-1 in the PDSCH 1520-1. The PHICH in the PDSCH may be located ator near the beginning of the PDSCH (e.g., at or near the fourth symbol),for example, to reduce power drain of the UEs or other devices. Forplural PHICH 1550 and 1560, the PHICH 1550 and 1560 may be spaced apartin a specified or predetermined location.

A PHICH for the SuppCell in a channel 1450, 1550, or 1560 may be definedwithin the PDSCH 1420 and 1520 of the licensed band. The presence ofthis channel 1450, 1550, or 1560 may be known by UEs that may be awareof the supplementary carrier. The knowledge may be limited to such UEs.The resource elements 1450-1 . . . 1450-N, 1550-1 . . . 1550-N, or1560-1 . . . 1560-N, which may be used for the additional PHICHresources may not be part of the resource elements allocated by theeNB/HeNB within the PDSCH 1420 and 1520. This procedure may enable(e.g., maintain) backward compatibility for UEs that use the licensedband (e.g., use may be limited to the licensed bands) because PDSCHallocations may not include resource elements reserved for thesupplementary carrier PHICH. Although the channel (e.g., which may becreated) is shown as located in the PDSCH, it may be located in thecontrol portion (e.g., the PDCCH) of each subframe or a combination ofthe PDSCH and PHICH.

The number of PHICH groups assigned may depend on the number ofsupplementary carriers being aggregated and the UL/DL configuration ofeach of these carriers. As a supplementary TDD carrier is added,removed, or reconfigured, the allocation of PHICH within the PDSCH areamay increase or decrease accordingly.

The location of the PHICH resources within a given OFDM symbol mayfollow the distribution defined in Rel-8 for LTE, e.g., to obtainfrequency diversity for the PHICH resources and to ensure that the PHICHresources are scaled per subframe based on the TDD UL/DL configuration.For a given supplementary carrier configuration, the eNB/HeNB may firstreserve the resource elements in the PDSCH area which may be used forthe PHICH. Actual PDSCH allocations for both UEs, which are using thesupplementary TDD carrier and those functioning in Rel-10 mode, may thenbe made with the remaining resources.

The resource allocation of the licensed FDD DL carrier with: no SuppCellis illustrated in FIG. 13; 1 SuppCell is illustrated in FIG. 14; and 2SuppCells is illustrated in FIG. 15. The PCFICH 1330, 1430, and 1530 mayindicate a PDCCH 1310, 1410, and 1510 (e.g., on the licensed band) thatmay include control symbols (e.g., the first three OFDM symbols 0, 1,and 2). The PHICH for the supplementary TDD carrier may be assigned fromthe beginning of the PDSCH 1320, 1420 or 1520 (e.g., the fourth OFDMsymbol) and may spread across the frequency spectrum, e.g., as may beaccomplished with the PHICH in Rel-8. These PHICH resources may be usedfor the supplementary TDD carrier. The amount of resources may change ona subframe-by-subframe basis, e.g., depending on the UL/DLconfiguration. Equation 1 and Table 1 may be used to determine thenumber of PHICH groups within each symbol. The joint or semi-staticlinking (e.g., as disclosed herein) may be used to adjust the number ofPHICH groups defined within the PDSCH of the licensed band on a percarrier basis. For example, the PHICH resources may be limited to theprimary CC. They may increase each time a new supplementary TDD carrieris added or they may exist on the PCC and on one or more SCCs. This maydepend on the number of supplementary TDD carriers being aggregated, andmay be changed by RRC signaling.

The number of PHICH groups, for example, in the fourth OFDM symbol of agiven licensed band CC may be establish from Equation 3:

N _(PHICH) _(_) _(supp) ^(group) =m·n _(supp) ·|N _(g) _(_) _(supp)(N_(RB) ^(DL)/8)|  (3)

where: the N_(g) parameter may be changed for a parameter that reflectsthe number of PHICH groups in the PDSCH area for that licensed bandcarrier; and additional multiplication factors may be added for thesubframe number (e.g., based on Table 1) and the number of supplementarycarriers linked to the particular licensed band carrier. Theseparameters, as with the N_(g) parameter, may be signaled using the SI.The MIB signaling may be used for N_(g), e.g., Rel-8/Rel-10 systems mayhave knowledge of N_(g) before they start to decode the PDCCH. N_(g)_(_) _(supp) and n_(supp) may be defined by RRC signaling, e.g., at thetime when the supplementary carrier is added. This may ensure that theDSS carriers may determine the appropriate resources for the PHICHwithin the data area, e.g., when it is to be used.

The OFDM symbol, which may follow the PDCCH area, may be used for thePHICH for the supplementary carrier. A UE, which is expecting theACK/NACK, may obtain the PHICH from the licensed band more quickly ifthe ACK/NACK is located in the initial symbol or beginning portion ofthe symbols. It may then turn off the front-end for the remainder of thesubframe if there is no data allocated to it. If the amount of the PHICHto be allocated for the supplementary carrier increases, subsequent OFDMsymbols may be used.

Although shown in FIGS. 13-15 as sets of 4 consecutive resource elements(e.g., as in Rel-10), the arrangement of the resource elements used forthe PHICH may be any number of resources elements.

The allocation may include one or more of the following. For a Rel-8and/or Rel-10 UE, the PHICH resource allocation may follow Rel-8 orRel-10. When a UE that may use the DSS bands is granted an UL allocationfrom a PCC or SCC for resources on the SuppC, the PHICH, which mayinclude the ACK/NACK for the UL transmissions on the SuppC, may belocated, for example, in the fourth OFDM symbol of the licensed carrierthat may have sent the UL grant. After completion, the location of thePHICH resource for the UE may be given by the initial PRB and the DMRScyclic shift value, e.g., Rel-8, and the total number of PHICH resourcesdefined on the fourth OFDM symbol may be given by Equation 3. The valueof parameters used to define the location of these resources (e.g., mand Ng) may be sent with the initial configuration of the supplementarycarrier before the UE may start to communicate in the DSS bands. Theremainder of resource blocks assigned for the PHICH in procedure 3 maybe unusable by Rel-8 and/or Rel-10 UEs. When the scheduler has one ormore transport blocks to be sent to a UE using the DSS bands in the samesubframe as the PHICH, it may use the remainder of the resource blocksused for assigning PHICH (e.g., as disclosed above) to send this data.This may be indicated by a resource allocation on the PDCCH, e.g., Rel-8and/or Rel-10. When a UE receives a DL allocation that may includeresource blocks used as described above, the UE may remove the PHICHfrom, for example, the OFDM symbol 4 prior to decoding a remainder ofthe resource block for data.

FIG. 16 illustrates an exemplary mapping 1600 of PHICH 1622 and 1624;1642 and 1644; and/or 1662 and 1664 to reserved resource blocks of acell (e.g., mapping for the PHICH using reserved resource blocks on thePDSCH of the Primary Cell or Secondary Cell. A new channel within thePDSCH region of the licensed band carriers may be created and mayinclude the reservation of one or more resource blocks for usingadditional PHICH resources.

The same of a similar linking (e.g., joint linking or semi-staticlinking used for CCEs) may be used for reserved resource blocks, exceptthat the additional PHICH 1622 and 1624, 1642 and 1644, and/or 1662 and1664, for the supplementary carrier may be found in reserved resourceblocks, e.g., instead of reserved CCEs. Two or more resource blocks maybe used and may be separated in the frequency domain, e.g., to ensuresome degree of frequency diversity for the PHICH. An individual PHICHgroup k may occupy multiple resource blocks to benefit from frequencydiversity.

For example, a set of n resource blocks may be equally separated infrequency domain, and their location may be defined through the cell ID(e.g., to avoid interference between or among the additional PHICHresources transmitted by, for example, separate eNBs/HeNBs). Linking maybe used such that, for example, each supplementary carrier may expect(e.g., search for) its PHICH resources on the PCC or a specific SCCbased on the established linking. Each PHICH may be multiplexed over then resource blocks, and the PHICH groups may be defined by assigning adifferent combination of carriers and OFDM symbols within the resourceblock.

The presence of a PHICH 1622 and 1624, 1642 and 1644, and/or 1662 and1664, in a reserved resource block 1610, 1620, or 1630 on a specificsubframe may depend on the subframe number and the specific UL/DLconfiguration of the SuppC. FIG. 16 shows an example in which 3 resourceblocks 1610, 1620, and 1630 may be reserved for the PHICH resources forthe supplementary TDD cell(s) and in which 12 symbols from a specificPHICH may be multiplexed over the three resource blocks. For example, inthe case of a system using normal CP and a PDCCH of length 3, 33 PHICHgroups may be defined (e.g., 264 PHICH resources are contemplated ifDMRS cyclic shifted).

The actual location of the Physical Resource Block (PRB) used for thePHICH may be changed on a subframe basis according to a predefinedhopping pattern, e.g., in order to ensure frequency diversity.

Certain subframes may be equipped with reserved resource blocks, e.g.,in order to exploit the nature of the TDD subcarrier, and to avoidhaving reserved resource blocks on each subframe. Table 2 or a similarmapping may be used to define which subframes may include these reservedresource blocks based on the UL/DL configuration. By changing the HARQtiming of the supplementary TDD carrier, e.g., compared to thedefinition in Rel-8, the number of subframes including reserved resourceblocks may be reduced (e.g., further) by allocating the PHICH for theACK/NACK in response to UL transmissions of different subframes to thesame reserved resource block.

FIG. 17 illustrates an exemplary allocation 1700 based PHICH resourcedefinition. The PDCCH 1710N or 1710N+1 may indicate the presence of areserved resource block 1722N or 1722BN+1 through an allocation (e.g., acreated allocation) made to a subset of UEs. A Radio Network TemporaryIdentifier (RNTI) 1712N or 1712N+1 (e.g., a multicast RNTI) may becreated, e.g., to define the set of UEs that have access to thesupplementary carriers and to the additional PHICH resources that may becarried in the reserved resource blocks on the data space or resources.In each subframe N and N+1 . . . where the reserved resource blocks1722N or 1722N+1 for the PHICH may be provided, an allocation on thePDCCH 1710N or 1710N+1 may be provided using the multicast RNTI 1712N or1712N+1. Each UE may locate the PHICH resource destined to it withinthis allocated resource block, e.g., in order to obtain the ACK/NACK itmay receive. If a UE is not expecting an ACK/NACK on the PHICH on agiven subframe N or N+1, it may ignore the allocation that may be madeon that particular subframe.

Such an allocation may allow the eNB to dynamically change frequencylocation of the resource block that is dedicated for the PHICH based onthe channel conditions, e.g., which may ensure that PHICH may beallocated a resource block that has relatively good channel conditionsfor the UEs to receive it. The number of PHICH resources may be changedon a subframe basis (e.g., if the eNB/HeNB determines that PHICHresources beyond what is currently in the PDCCH space are not needed,this allocation may not be made for one or more subframes). For example,the M-RNTI 1712N may indicate a particular location and/or size of thePHICH 1722N in subframe N and the M-RNTI 1712N+1 may indicate aparticular location and/or size of the PHICH 1722N+1 in subframe N+1.The M-RNTI may selectively be included in the PDCCH, e.g., to providethe addition PHICH in a subframe, for example, subframe N or N+1.

The PHICH resources may be distributed in a predetermined pattern (e.g.,evenly across the data space or resources, periodically across the dataspace or resources, in a particular region of the data space orresources, etc.). This may be an alternative to allocation. For evendistribution of the PHICH resources, the PHICH resources may occupy asmall percentage (e.g., below a threshold percentage) of the resourceelements of each resource block. The UEs may be able to decode theassigned resource blocks successfully, e.g., with small degradation,because a small percentage of resource blocks may be modified in orderto add the distributed PHICH data.

A multiplexing operation may be used to send ACK/NACK information withactual data allocations (e.g., ACK/NACK multiplexed with data), forexample, as described below. FIG. 18 illustrates an exemplary ACK/NACKmultiplexing operation using an ACK/NACK modulator 1800. The ACK/NACKmodulator 1800 may include a plurality of ACK/NACK chains or processorunit 1802-1 . . . 1802-N, each may respectively include, for example, anencoder 1810-1, 1810-N (e.g., a robust PHICH encoder), a modulator1820-1 . . . 1820-N (e.g., a BPSK, QPSK or other modulator), and/or amultiplexer 1830-1 . . . 1830-N that may use a scrambling code. Eachprocessor unit 1802-1 . . . 1802-N may output a predetermined number ofsymbols that may be input to a multiplexer 1880. A transport block(e.g., variable sized) may be input to transport block processing unit1805 including a CRC unit 1850, a segmentor unit 1855, a turbo codingunit 1860, a HARQ unit 1865, a scrambling unit 1870, and/or a modulationunit 1875. The output of the transport block processing unit may beinput to the multiplexer 1880 to multiplex the data output from thetransport block processing unit 1805, e.g., with a predetermined numberof symbols from each of the processing units 1802-1 . . . 1802-N. Theout of the multiplexer 1880 may be input to a resource block mapper(RBM) that may map the resource blocks prior to OFDM modulation. Theresource blocks may be mapped according to predetermined rules andalgorithms, e.g., Rel-10. Although the ACK/NACK modulator 1800 may beshown with separate processing units, any number of such units or asingle unit may be used.

The robust PHICH encoding may include an n-bit repetition, where n maybe larger than a threshold number (e.g., larger than 3 which may be usedfor PHICH encoding in the PDCCH). The value n may be predetermined ormay be dynamically set based on the channel quality (e.g., signaling bythe eNB, for example, via RRC signaling). When the channel quality ofthe component carrier that is carrying the multiplexed PHICH changes,the value n may be adjusted. For example, when the channel qualitydegrades, the value n may be increased and when the channel qualityimproves the value n may be decreased, e.g., to maintain a BER, or otherchannel quality indicator, for the PHICH at or below a threshold value.In lieu of or in addition to the RRC signaling of channel quality, thevalue n may be selected based on or derived from the CQI reported by theUE, which may receive the transport block comprising the embedded PHICH.For a low quality channel with a low CQI, the value n may be set larger(e.g., the eNB and UE may be aware of this based on the CQI reported bythe UE). Convolutional encoding may be employed to implement the robustPHICH encoding, where the code rate may be set higher than the code rateof the PDCCH channel.

For example, the ACK/NACK multiplexing operation may include theACK/NACKs for each Supplementary CC (SuppCC) being separately processedfor multiplexing onto the data space or resources. The PHICH for theSuppCC may be sent using the PDSCH allocations made to the UE for DLdata on the licensed band (e.g., the PCC or the SCC). The ACK/NACK forUL data of the SuppCC may be multiplexed on or piggybacked with DL dataintended for the same UE on the PCC and/or SCC. This may not affect thedata region of, and may be backward compatible with, Rel-8 and Rel-10UEs.

The eNB/HeNB may multiplex the data for a transport block to be sent toa UE with the ACK/NACK destined for that UE. The ACK/NACK of each SuppCCmay be encoded, e.g., using a separate chain or series as shown in FIG.18.

A similar circuit for demodulating the ACK/NACK of FIG. 18 may beimplemented using the reverse operations to those described regardingFIG. 18. For example, a processor may be configured to perform one ormore of the following: unmap resource blocks of the data space orresources; demultiplex the unmapped resource blocks of the data space orresources; or individually decode the confirmation transmission and thedata of the data space or resources. The encoded confirmationtransmission may have a higher decoding reliability than the encodeddata of the data space or resources to regenerate the ACK/NACKs inputtedto ACK/NACK modulator 1800.

The ACK/NACK for UL transmissions on different supplementary TDDcarriers may be bundled on a single ACK/NACK. This may result in asingle chain (e.g., and may use a single processing unit).

Due to the more stringent BER used for PHICH compared with the PDSCHdata, a more robust encoding for the PHICH in conjunction with, forexample BPSK modulation may be used. The encoding used for PHICH may bemore robust than 3-bit repetition, e.g., Rel-8 PHICH.

Since data and ACK/NACKs may have different coding, scrambling, and/ormodulation, the multiplexing, for example at multiplexer 1880, of thedata and the ACK/NACKs may be accomplished following each process. Theresource elements that may carry the ACK/NACK may be reserved for aspecific UE; no multiplication by an orthogonal code may be used. Thismay eliminate multiple PHICH being transmitted on a single PHICH groupand may maintain the same number of PHICH resources, e.g., regardless ofwhether MU-MIMO may be used.

The multiplexing operation, e.g., by the multiplexer 1880, may performtime and frequency multiplexing of the PHICH with the remainder of thetransport block prior to mapping to the resource blocks, e.g., as may bethe case with UCI on the PUSCH. The PDSCH allocation may take intoaccount the additional resource elements used for the ACK/NACK. Themapping of transport block size (e.g., given some resources reserved forthe ACK/NACK) may be used by UEs with DSS capability (e.g., limited touse by the UEs with DSS capability), which may provide backwardcompatibility of Rel-8 and Rel-10 UEs. Each DSS-capable UE may knowduring which subframe it may expect an ACK/NACK from the eNB/HeNB; thisinformation may be used by the UE to trigger de-multiplexing in order toseparate ACK/NACKs (e.g., for each SuppCell that may transmit one of theACK/NACKs) from the transport block, e.g., and may use the mapping forthe effective transport block size. A single standard mapping (e.g., toresource elements) of the symbols associated with the ACK/NACK may beused and may depend on the number of Supplementary CCs from which the UEsimultaneously expects an ACK in addition to the number of ACK/NACK bitscoming from each supplementary carrier (e.g., 2 bits for an UL-MIMO).This information may be made available to each UE via RRC signaling.

The component carrier that carries the ACK/NACK (multiplexed with thedata) may correspond to the one which had been used to send the ULallocation on the supplementary carrier. The specific licensed carrierthat may include the ACK/NACK may be determined using previous Releaserules.

Given the robustness of the PHICH, PHICH resources associated withsupplementary cells may be piggybacked on the primary cell resourceallocations. This may be restrictive when secondary cells may be presentbecause it may reduce the probability that a PHICH may be piggybacked ona given subframe and may increase the frequency of occurrence offallback mechanisms, e.g., as disclosed herein. The PHICH may bepiggybacked on a best available licensed cell (e.g., first primary, thensecondary) that includes a data allocation for the particular UE.

Symbols associated with the PHICH across the transport block may bedistributed, e.g., to provide robustness to frequency selective fading.The mapping may be dependent on the allocation type (e.g., type 0, type1, and/or type 2), and/or the number of resource blocks assigned.

One or more fallback mechanisms may be used. For example, when no datais allocated for a UE on a target subframe, a fallback mechanism may beused. When no data is available for a particular UE on a given subframeand the eNB/HeNB may need to send an ACK/NACK for an UL transmission onthe supplementary carrier, a fallback may be used, e.g., using thePDCCH. In such a case, the ACK/NACK may be sent through a DCI format onthe PDCCH, which may not allocate resource blocks in PDSCH, but may sendthe symbols (e.g., 12 symbols) for the ACK/NACK to the specific UE. Thesending may be limited to 12 symbols. For example, PDCCH format 1C maybe used to send the ACK/NACK, e.g., this DCI format may be small and mayalready be used for special communication such as sending informationfor MCCH change notification. A predefined value of the modulation andcoding scheme may be used to flag (e.g., indicate) the format to be aDCI format 1C that includes the ACK/NACK. The corresponding ACK/NACKsymbols may be sent in the place of the resource block assignment. TheACK/NACK may be sent in a single resource block allocation to the UE(e.g., using allocation type 2), which may allow no change in theexisting DCI formats.

PHICH multiplexing with data may include one or more of the following.The UE may expect that an ACK/NACK for an UL transmission on the SuppCbe made in subframe n to be sent by the eNB/HeNB on frame n+k. The valueof k may be fixed (e.g., as in FDD) or may be based on the TDD UL/DLconfiguration. RRC signaling may specify which timing is to be used. Ifthe scheduler has data to be sent to the particular UE in subframe n+k,the scheduler may multiplex the data with the ACK/NACK. If the schedulerdoes not have data to be sent to the particular UE in subframe n+k, thescheduler may send the ACK/NACK using the predefined DCI format (e.g.DCI format 1C). The UE, in subframe n+k, may determine the location ofthe ACK/NACK based on the received DCI. If the predefined DCI format isaddressed to the UE, the UE may use the DCI itself to find the ACK/NACKinformation. If the UE receives an allocation DCI format, the UE maydemultiplex the ACK/NACK from the resource blocks, e.g., prior totransport block decoding.

ACK/NACK multiplexing may be used for the ACK/NACK associated with ULtransmission limited to the supplementary carrier (e.g., in order topromote backward compatibility). The above may be extended to ULtransmission on the licensed carriers, which may for example eliminatethe need for a PHICH altogether. The ACK/NACK may be multiplexed withthe data over the supplementary carrier, e.g., rather than the PCC orSCC.

The DSS bands may be less reliable. It may be less desirable to locatethe PHICH on these bands. There may be scenarios in which the PHICH maybe more reliable when located on the DSS bands. For instance, the SuppCmay be located on a band that may be leased from or brokered to aspecific operator and the operator may have some guarantee of thequality of the SuppC. In this case, some or all of the ACK/NACKs for ULtransmissions may be sent on the supplementary TDD carrier. The UL grantfor the transmission on the Supplementary TDD carrier may be sent on thelicensed carrier or on the supplementary carrier, e.g., depending onvarious criteria as described herein. The licensed carrier may be usedfor ACK/NACK for UL transmissions that occur in the licensed band. Thelicensed carrier may be used for one or more ACK/NACK corresponding toUL transmissions from the supplementary TDD carrier.

If the PHICH resources on a TDD carrier are sufficient for sending theACK/NACK for UL PUSCH transmissions for that carrier and if the PHICHresources on the licensed band are sufficient for UL transmissions onthe licensed band, a total number of PHICH resources available (e.g.,when the TDD supplementary carrier PHICH resources are pooled with thelicensed band PHICH resources) may be sufficient for a configuration ofsecondary and supplementary carriers. PHICH resources may be assigned toavoid collisions.

FIG. 19 illustrates an exemplary supplementary cell uplink (UL) grantoperation 1900. An UL grant 1 may be provided from the eNB/HeNB 1910over the PrimCC (e.g., the primary licensed FDD carrier component). TheUL grant 1 may indicate that UL transmission 1 by the UE 1920 is to besent over the PrimCC. The UE 1920 may send a UL transmission 1 over thePrimCC to the eNB/HeNB 1910. During the UL grant, the MIB may be sentfrom the eNB/HeNB 1910 to the UE 1920 and may specify, for example, thelocation including the CC (e.g., the PrimCC) used to transmit theACK/NACK 1 and/or the size of the PHICH resources for the ACK/NACK 1that is to be associated with the UL transmission 1 by the UE 1920.

After UL grant 1, an UL grant 2 may be provided from the eNB/HeNB 1910over the PrimCC. The UL grant 2 may indicate that the UL transmission 2by the UE 1920 is to be sent over the secondary CC. The UE 1920 may sendthe UL transmission 2 over the secondary CC to the eNB/HeNB 1910. Duringthe UL grant 2, the MIB may be sent from the eNB/HeNB 1910 to the UE1920 and may specify, for example, the location including the CC (e.g.,the PrimCC) used to transmit the ACK/NACK 2 and/or the size of the PHICHresources for the ACK/NACK 2 that is to be associated with the ULtransmission 2 by the UE 1920.

An UL grant 3 may be provided from the eNB/HeNB 1910 over theSupplementary TDD CC. The UL grant 3 may indicate that the ULtransmission 3 by the UE 1920 is to be sent over the Supplementary TDDCC. The UE 1920 may send the UL transmission 3 over the SupplementaryTDD CC to the eNB/HeNB 1910. During the UL grant 3, the MIB may be sentfrom the eNB/HeNB 1910 to the UE 1920 and may specify, for example, thelocation including the CC (e.g., the Secondary CC) used to transmit theACK/NACK (e.g., ACK/NACK 3 and/or the size of the PHICH resources forthe ACK/NACK 3 that is to be associated with the UL transmission 3 bythe UE 1920).

FIG. 20 illustrates an exemplary supplementary ACK/NACK UL transmission2000. An UL grant 1 may be provided from the eNB/HeNB 2010 over thePrimCC (e.g., the primary licensed FDD carrier component). The UL grant1 may indicate that UL transmission 1 by the UE 2020 is to be sent overthe PrimCC. The UE 2020 may send the UL transmission 1 over the PrimCCto the eNB/HeNB 2010. During the UL grant, the MIB may be sent from theeNB/HeNB to the UE 2020 and may specify, for example, the locationincluding the CC (e.g., the PrimCC) used to transmit the ACK/NACK 1and/or the size of the PHICH resources for the ACK/NACK 1 that is to beassociated with the UL transmission 1 by the UE 2020.

After UL grant 1, an UL grant 2 may be provided from the eNB/HeNB 2010over the PrimCC. The UL grant 2 may indicate that UL transmission 2 bythe UE 2020 is to be sent over the secondary CC. The UE 2020 may send ULtransmission 2 over the secondary CC to the eNB/HeNB 2010. During the ULgrant 2, the MIB may be sent from the eNB/HeNB 2010 to the UE 2020 andmay specify, for example, the location of the CC (e.g., the PrimCC) usedto transmit the ACK/NACK 2 and/or the size of the PHICH resources forthe ACK/NACK 2 that is to be associated with the UL transmission 2 bythe UE 2020.

An UL grant 3 may be provided from the eNB/HeNB 2010 over the SecondaryCC. The UL grant 3 may indicate that UL transmission 3 by the UE 2020 isto be sent over the Supplementary TDD CC. The UE 2020 may send a ULtransmission 3 over the Supplementary TDD CC to the eNB/HeNB 2010.During or subsequent to the UL grant 3, RRC signaling may be sent fromthe eNB/HeNB 2010 to the UE 2020 and may specify, for example, thelocation including the CC (e.g., the Supplementary TDD CC) used totransmit the ACK/NACK (e.g. the ACK/NACK 3 and/or the size of the PHICHresources for the ACK/NACK 3 that is to be associated with the ULtransmission 3 by the UE 2020). The UE 2020 may be a beyond Rel-10 or aDSS UE, e.g., because the ACK/NACK 3 was not on the same CC as itscorresponding UL grant 3.

The scheduler may be restricted to not employ cross-carrier schedulingfor the UL. The UL grants may be scheduled from the cell (e.g., primary,secondary, or supplementary) where the PUSCH transmission may occur, andthe ACK/NACK for that transmission may be sent on the same cell. Crosscarrier scheduling may be used (e.g., limited to use) for the licensedband.

The UL grants made for PUSCH transmission on the supplementary cell maybe accomplished via the PDCCH on the same supplementary cell; theACK/NACKs for these transmissions use (e.g., may be limited to using)the resources on the supplementary cell and may be collision-free. Thetiming of the expected ACK/NACK may be derived, for example, from Rel-8specific to the carrier (e.g., TDD or FDD), where the scheduling hasbeen accomplished such that additional signaling may not be needed fordetermining the ACK/NACK timing.

The scheduler may specify (e.g., along with each UL grant) the componentcarrier on which the ACK/NACK may be received, which may allowflexibility for cross-carrier scheduling and the PHICH location. Thescheduler may have the ability to perform cross carrier scheduling fromthe licensed band for the UL associated with the DSS band and mayeliminate the uses for the PDCCH on the supplementary TDD carrier. Thescheduler may have the flexibility of using the pool of PHICH resources(e.g., licensed and supplementary) on a dynamic basis. Collisionavoidance may be achieved using an extra degree of freedom, for example,a third degree of freedom. For example, one or more of the following mayapply: the eNB/HeNB may schedule different UEs by specifying a differentstarting PRB; if the same starting PRB is scheduled between differentUEs, a different cyclic shift may be assigned for the DMRS; or ifassigning a different cyclic shift is not possible due to the number ofuser involved in UL-MIMO, the PHICH resources to be used by the two UEsmay be taken from different carriers.

A field may be added to the UL grant DCI format (e.g., DCI format 0),which may specify the CC used for PHICH signaling. For each SuppCellconfigured, the upper layer may indicate (e.g., via RRC messaging orsignaling) which DL CC the upper layer is to receive the PHICH, whichmay spread the load in the control space or resources, e.g., if multipleUEs assigned to a given PrimCell are active at the same time.

The timing of the ACK/NACK relative to the UL using prior rules for TDDor FDD may cause problems due to scheduling for DSS UEs in which thePUSCH transmission is over the licensed (FDD) carrier, and the PHICH onthe supplementary TDD carrier may be used to send ACK/NACK to the DSSUE. In such a case, the supplementary TDD carrier may not have asubframe configured for DL at the subframe when it is to send theACK/NACK. This may be removed from the scheduling scenarios used by thescheduler or a rule may be enforced such as scheduling the ACK/NACK onthe next available DL subframe.

The UEs allowing for DSS operation may follow different rules for ULgrants made for supplementary carriers and licensed band carriers, e.g.,which may avoid specification of the location of the PHICH and maymaintain backward compatibility. For UL transmissions made on thelicensed band as well as for Rel-10 UEs, the UL grant as provided for inRel-10 may apply (e.g., the PHICH for the UL transmission may be locatedon the CC where the grant was sent). For UL transmissions made on thesupplementary carrier, the PHICH may be sent on the same supplementarycarrier as the UL transmission. This may provide backward compatibilityand collision avoidance. For example, UL heavy configurations may notoccur given the PHICH resources on the supplementary TDD carrier may beemployed. The PDCCH may or may not be transmitted on the supplementaryTDD carrier.

By sending PHICH on the TDD supplementary carrier, the PHICH resourceson a TDD carrier may have already been defined that automatically scalethese resources based on the UL/DL configuration and/or the subframenumber. The supplementary carrier may not have the reliability level toprovide for the PHICH (e.g., a Bit Error Rate at or above a thresholdlevel). One or more of the following may apply: as long as the systemevaluates the supplementary carrier to be reliable (e.g. no other usersdetected or good quality measurements for BER, SNR, and/or SIR, etc.),the supplementary carrier may be used to send the PHICH; or when thesupplementary carrier quality drops below a threshold (e.g.,pre-established or specified for which the supplementary carrier may begood enough to send data but not the ACK/NACKs), the number of PHICHresources on the licensed FDD carrier may be dynamically increased,e.g., to send ACK/NACKs on the licensed band. One or more of thefollowing may be used for the above. During initial system configurationor initial configuration of the supplementary carrier, the UE andeNB/HeNB may perform measurements of the supplementary carrier. If thequality of this carrier for a particular UE is above a certainthreshold, the PHICH may be configured on the supplementary carrier(e.g., the Rel-8 TDD mechanism for PHICH allocation may be used). If thequality is at or below the threshold, one of the PHICH extensionmechanisms (e.g., as disclosed herein) may be used. The decision and thePHICH configuration may be sent to the UE using RRC signaling.

The UE may continue to monitor the quality of the supplementary carrierin comparison to the threshold. If a change is detected (e.g., thequality goes from being above the threshold to below the threshold, orvice versa), the eNB/HeNB may change the mechanism in which PHICH isconfigured. This change may be communicated to the UE through RRCsignaling.

Although different mechanism have been illustrated for enabling ACK/NACKresource allocations to enable the use of supplementary CCs, eachmechanism may be an operational mode for accomplishing such allocationsand the system may selectively choose between or among (e.g., two ormore) of the various modes based on operational conditions includingmeasured channel interference, UE power supply capacity, and theexistence of Rel-8 and Rel-10 devices on the primary, secondary, and/orsupplementary CCs, among others.

FIG. 21 illustrates an exemplary mechanism 2100 of allocating messageresources between or among first and second carriers in a wirelesscommunication network. The method may include one or more of thefollowing. At 2110, a first wireless device (e.g., the base station,gateway, eNB or HeNB, etc.) may send an uplink grant, for example as afirst message, for granting uplink space or resources on the firstcarrier. At 2120, the first wireless device may send to a secondwireless device (e.g., a UE, wireless radio, computer, notebook, and/orWRTU, etc.) a message resource allocation signal, as a second messagedifferent from the first message, indicating one of the first or secondcarriers for allocating a message resource.

For example, the sending of the message resource allocation signal mayinclude the first wireless device sending information in the messageresource allocation signal indicating an allocation flag, which mayestablish one or more of the following: there may be confirmationtransmission resources in the data space or resources of one of thefirst or second carriers; there may be a confirmation transmissionresource channel in the data space or resources of one of the first orsecond carriers; or multiplexing of the confirmation transmission withdata of the data space or resources of one of the first or secondcarriers. The allocation flag may be sent responsive to the messageresources for confirmation transmission not being sufficient to handleconfirmation transmissions associated with the carriers used tocommunicate between the first and second wireless devices.

FIG. 22 illustrates an exemplary mechanism 2200 of allocating messageresources between or among a plurality of carriers in a wirelesscommunication network. In FIG. 22, 2200 may include, at 2210, a firstwireless device (e.g., the base station, gateway, eNB or HeNB, etc.)that may send an uplink grant for granting uplink space or resources onthe first carrier. The uplink grant may indicate a first transmissionacknowledgment allocation. At 2220, the first wireless device may sendto a second wireless device (e.g., a UE, wireless radio, computer,notebook, and/or WRTU, etc.) a second transmission acknowledgmentallocation, which may be different from the first acknowledgmentallocation indicated by the uplink grant. The second transmissionacknowledgment allocation may indicate one of the plurality carriers forallocating the transmission acknowledgment of an uplink transmissionassociated with the uplink grant. At 2230, the first wireless device mayreceive from the second wireless device, the uplink transmissionassociated with the uplink grant. At 2240, the first wireless device maysend to the second wireless device an uplink transmission acknowledgmenton the indicated one of the plurality of carriers in accordance with thesecond transmission acknowledgement allocation. The second wirelessdevice may function in a complementary fashion to the first wirelessdevice such that they as paired or matched receivers/transmitters.

The multiplexing of the confirmation transmission with the data of thedata space or resources may include individually encoding theconfirmation transmission and the data in the data space or resources(e.g., the encoded confirmation transmission may have a higher decodingreliability than the encoded data of the data space or resources);multiplexing the encoded confirmation transmission with the encodeddata, e.g., as a multiplexed result; and/or mapping the multiplexedresult to resource blocks in the data space or resources.

The confirmation transmission resource channel may be located in abeginning region of the data space or resources of one or moresubframes.

The processor may adjust the value of the allocation flag based on anumber of supplementary carriers used to communicate between the firstand second wireless devices and may determine the sufficiency to handlethe confirmation transmissions based on the adjusted value of theallocation flag.

At 2130, the first wireless device may receive from the second wirelessdevice, an uplink transmission associated with the uplink grant. At2140, the first wireless device may send to the second wireless device,an uplink transmission confirmation on the message resource of one ofthe first or second carriers indicated by the message resourceallocation signal.

A processor of the first wireless device may determine which one of thefirst or second carriers may carry the transmission confirmation basedon at least one characteristic of the first or second carriers (e.g.,whether the first and/or second carrier is licensed or in the DSS bands,and/or whether they have sufficient PHICH resources, etc.). For example,the processor may determine the first carrier is to carry thetransmission confirmation, e.g., responsive to the first carrier being alicensed carrier and the second carrier being a DSS carrier.

The message resource allocation signal may be sent via a Radio ResourceControl (RRC) signal.

Control channel elements in the data space or resources of the firstcarrier intended for confirmation transmissions may be reserved, each ofthe reserved control channel elements may be linked (e.g.,semi-statically linked) to a respective supplementary carrier. Theuplink transmission confirmation may be transmitted via the firstcarrier using the control information space or resources allocated tothe reserved control channel elements. The reserved control channelelement may be linked to the supplementary carrier used for the uplinktransmission (e.g., that is confirmed by the transmission confirmation).

In certain exemplary embodiments, the reserved control channel elementsare maintained in the control information space or resources of thefirst carrier for confirmation transmissions regardless of uplink grantsby the first wireless device.

In certain exemplary embodiments, the control channel elements in thecontrol information space or resources of the first and second carriersmay be reserved for uplink confirmation transmissions and the uplinktransmission confirmation may be transmitted via one of the first orsecond carriers using the control information space or resourcesallocated to the reserved control channel elements.

The second carrier may be a frequency division duplexing (FDD) carrierin a DSS band and the FDD carrier may be dynamically switched between afirst operating mode in which the FDD carrier is uplink and a secondoperating mode in which the FDD carrier is downlink. For example, in thefirst operating mode, the uplink transmission confirmation may beallocated to the message resource of one of the first or second carriersindicated by a message resource allocation message or signal, and in thesecond operating mode, the uplink transmission confirmation previouslyallocated by the message resource allocation message or signal may beunallocated. The first device may send to the second device a switchingsignal to switch the FDD carrier between the first and second modes.

The allocation of message resources may be modified when one or morecarriers used to communicate between the first and second wirelessdevices is changed.

Resource blocks may be reserved in the data space or resources of thefirst carrier for confirmation transmissions and each of the reservedresource blocks may be linked to a respective supplementary carrier suchthat the uplink transmission confirmation may be transmitted via thefirst carrier using the data space or resources allocated to thereserved resource blocks (e.g., which may be linked to the supplementarycarrier used for the uplink transmission).

The first device in a control area of each respective subframe mayestablish an identifier that indicates a location of the reservedresource blocks in a respective subframe and an adjustment of thelocation of the reserved resource block for one or more subsequentsubframes may occur in accordance with a measured transmission quality(e.g., CQI).

Resource blocks in the data space or resources of the first and secondcarriers for uplink confirmation transmission may be reserved such thatthe uplink transmission confirmation may be transmitted via one of thefirst or second carriers using the data space or resources allocated tothe reserved resource blocks (e.g., which may be identified by theM-RNTI).

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of non-transitory computer-readable storage mediainclude, but are not limited to, a read only memory (ROM), random accessmemory (RAM), a register, cache memory, semiconductor memory devices,magnetic media such as internal hard disks and removable disks,magneto-optical media, and optical media such as CD-ROM disks, anddigital versatile disks (DVDs). A processor in association with softwaremay be used to implement a radio frequency transceiver for use in aWTRU, UE, terminal, base station, RNC, or any host computer.

1-16. (canceled)
 17. A method implemented in a wireless transmit/receiveunit (WTRU), the method comprising: receiving configuration informationassociated with a supplementary cell that uses an unlicensed band;transmitting data to a network via the supplementary cell; and receivingfeedback associated with the data from the network via a PhysicalDownlink Shared Channel (PDSCH) or a Physical Downlink Control Channel(PDCCH), the PDSCH and the PDCCH being carried on a licensed band,wherein, when the feedback is received on the PDSCH, the feedback ismultiplexed with downlink data, and wherein, when the feedback isreceived on the PDCCH, the feedback is received in a Downlink ControlInformation (DCI) format that comprises ACK/NACK information.
 18. Themethod of claim 17, wherein the ACK/NACK information is received by theWTRU in a resource block assignment.
 19. The method of claim 18, whereinthe resource block assignment is a single resource block using a type 2allocation.
 20. The method of claim 17, wherein the DCI format is format1C.
 21. The method of claim 17, wherein the feedback is received on aprimary component carrier.
 22. The method of claim 17, wherein theunlicensed band comprises TV white space.
 23. A wirelesstransmit/receive unit (WTRU) comprising: a processor configured to:receive configuration information associated with a supplementary cellthat uses an unlicensed band; transmit data to a network via thesupplementary cell; and receive feedback associated with the data fromthe network via a Physical Downlink Shared Channel (PDSCH) or a PhysicalDownlink Control Channel (PDCCH), the PDSCH and the PDCCH being carriedon a licensed band, wherein, when the feedback is received on the PDSCH,the feedback is multiplexed with downlink data, and wherein, when thefeedback is received on the PDCCH, the feedback is received in aDownlink Control Information (DCI) format that comprises ACK/NACKinformation.
 24. The WTRU of claim 23, wherein the ACK/NACK informationis received in a resource block assignment.
 25. The WTRU of claim 24,wherein the resource block assignment is a single resource block using atype 2 allocation.
 26. The WTRU of claim 23, wherein the DCI format isformat 1C.
 27. The WTRU of claim 23, wherein the processor is configuredto receive the feedback on a primary component carrier.
 28. The WTRU ofclaim 23, wherein the unlicensed band comprises TV white space.